Apple Mail on Mac Not Syncing Microsoft 365: EWS Shutdown Explained and How to Fix It

What is happening to Apple Mail and Microsoft 365

Microsoft has started disabling Exchange Web Services (EWS) by default in Exchange Online, and Apple's Mail and Calendar apps on Mac still rely on EWS to sync Microsoft 365 work accounts. When EWS is switched off for your organization, Mail on your Mac can stop receiving new messages and calendar changes even though nothing looks broken on your Mac. Microsoft's own web interface and the Outlook apps keep working because they use newer connections.

According to MacRumors, which reported the change on October 1, 2026, the default switch-off begins in October 2026 and EWS is scheduled to be permanently shut down in Exchange Online on April 1, 2027, with no extensions currently planned. The same report says Microsoft stopped adding new features to EWS back in 2018 and announced the retirement plan in 2023. So this is a long-announced change that is now reaching real inboxes, not a surprise bug.

Apple says it is working with Microsoft to move Mail and the related apps to the Microsoft Graph API in a future macOS update. As of the MacRumors report, that had not shown up in the versions the author tested. We could not confirm on a primary Apple page which macOS release will carry the change, so treat any specific version number you read elsewhere as unconfirmed until Apple publishes release notes.

This guide is written for two readers. If you are an everyday user whose Mac suddenly stopped fetching work email, the decision table and the workarounds below get you reading mail again today. If you are the Microsoft 365 administrator for a small business, the admin section shows the one setting we could confirm on a Microsoft page, the questions to ask before you change it, and a calm migration plan before the April 2027 deadline.

Is this my problem? A decision table

You are affected if your Mac's Apple Mail or Calendar app connects to a Microsoft 365 work or school account using the Exchange account type. You are not affected if you read the same mailbox in a web browser, in Outlook, on an iPhone or iPad, or if your company runs its own on-premises Exchange server. The table below covers the common situations we see in small offices.

The word "likely" matters. Microsoft is rolling the change out in stages, so some Macs lose sync today, some next week, and some after the administrator makes a choice. A Mac that still syncs today is not proof that you are safe. If the account uses the Exchange type in Mail, plan as if the break is coming.

Symptoms: how the break shows up on your Mac

The most common sign is silence: new messages stop arriving in Apple Mail while the same mailbox keeps receiving mail in a browser. Because the Mac does not always show a clear error, many people blame Wi-Fi or the Mac itself and waste an afternoon restarting things that are fine.

• New email appears in Outlook on the web or on your phone, but not in Mail on the Mac.
• Calendar invitations accepted on the phone never show up in Calendar on the Mac, or meetings you create on the Mac are missing for colleagues.
• Mail asks for your password repeatedly even though you typed it correctly, or the account shows a warning icon in Mail settings.
• Sent messages sit in the Outbox, or the account is listed as offline while other accounts work.
• Contacts, Notes or Reminders linked to the Exchange account stop updating.

Before you assume this is the EWS change, rule out the boring causes: an expired password, an account that your administrator reset, a conditional access rule, or a plain internet outage. The quickest test is the browser. Sign in to Outlook on the web with the same account. If the browser also fails, the problem is the account itself, not the EWS change, and our guide to fixing Outlook when it is not working is a better starting point. If the browser works and Apple Mail does not, keep reading.

How to check your account type in Mail on a Mac

Open System Settings, choose Internet Accounts, and click your work account: if the account type is listed as Exchange, Apple Mail is talking to Microsoft 365 through Apple's Exchange connection, which is the one that depends on EWS. Menu names shift slightly between macOS releases, so treat the wording below as a guide rather than a script.

1. Click the Apple menu, then System Settings.
2. Scroll the sidebar to Internet Accounts.
3. Look at the list of accounts. Each entry shows a name and a type such as iCloud, Google, Exchange, Microsoft Exchange or Other.
4. Click your work account. Note which apps are switched on for it: Mail, Contacts, Calendars, Notes, Reminders.
5. Open the Mail app, choose Mail, Settings, Accounts, and select the same account. The Account Information tab shows a description and whether the account is enabled.

If your account is a plain IMAP account that someone set up manually, or a Google or iCloud account, this EWS change is not the reason it stopped. If it is an Exchange account tied to your company address, you are in the affected group. Write down the exact email address and the name of the server if Mail shows one, because your administrator may ask for it.

One more check saves a lot of confusion: look at how many Microsoft accounts you have. Some people have both a personal Outlook.com address and a company address on the same Mac. Only the company one, hosted in Microsoft 365, is the subject of this article. A quick way to tell is the domain. A company domain such as yourname@yourcompany.com sits in Microsoft 365 if your office uses it. A personal outlook.com or hotmail.com address is a separate consumer service.

User workarounds: read your mail today

The fastest safe workaround is to open Outlook on the web in a browser and sign in with your work account, which takes about one minute and is unaffected by the EWS change. After that you can decide at your own pace between the Outlook app for Mac and waiting for your administrator.

Workaround 1: Outlook on the web (one minute, free)

Open any browser, go to the Microsoft 365 sign-in page used by your company, and open Mail. Pin the tab or save it as a bookmark. Calendar is one click away in the same interface. You lose offline access and the Apple look, but you keep working. For a person who is away from the office or in the middle of a deadline, this is the right first move.

Workaround 2: the Outlook app for Mac

MacRumors names Microsoft's Outlook app as a Graph-compatible client, which is the direction Microsoft is pushing. If your company licence includes the desktop apps, you can install Outlook from your Microsoft 365 account page and sign in. Update to the latest version first. We could not confirm on a primary page which Outlook for Mac build is required, so install the newest one offered rather than an old installer from a shared drive. Your mailbox lives on the server, so your messages appear once you sign in; local drafts and rules in Apple Mail do not move across by themselves.

Workaround 3: keep using your iPhone or iPad

MacRumors reports that iPhone and iPad use Exchange ActiveSync and are not affected. If your phone already has the account, it keeps syncing. This is a stopgap, not a plan, because typing long replies on a phone is slow, but it prevents missed messages while you sort out the Mac.

Workaround 4: ask your admin to restore EWS temporarily

Administrators can restore EWS access, according to MacRumors. If you are a user, the message to send is short: "Apple Mail on my Mac stopped syncing since EWS was disabled by default. Can you check whether EWS is enabled for our tenant and tell me the plan before April 1, 2027?" The next section explains what that request involves and why a careful administrator may not simply say yes forever.

What not to do

• Do not delete and re-add the account in a panic. It will not fix a server-side switch, and it can remove cached messages you have not yet seen elsewhere.
• Do not install random "Exchange fixer" tools. No third-party utility can turn a protocol back on inside your company's Microsoft 365 tenant.
• Do not use a personal email forward to work around it for sensitive mail. Forwarding company mail to a personal inbox can break company policy and, in Quebec, privacy obligations under Law 25.
• Do not share your password with a colleague so they can check mail for you. Use delegate access or a shared mailbox instead.

If the issue is not the EWS change after all, for example you cannot sign in at all or an account looks compromised, stop and read our guide on recovering a hacked Microsoft Outlook account before changing anything.

For Microsoft 365 admins: restoring EWS and what we can confirm

The admin lever we could confirm on a Microsoft page is the organization-level EWS switch in Exchange Online PowerShell: the Set-OrganizationConfig cmdlet has an EwsEnabled parameter that turns EWS on or off for the organization, plus allow-list and block-list parameters that limit which applications may use EWS. This is documented on Microsoft Learn. What we could not confirm is the exact new default behavior that Microsoft is applying during the rollout, so read your own message center notices before you change anything.

MacRumors reports that administrators can restore EWS access and that organizations can choose to keep EWS running until the permanent shutdown. In practical terms, an admin has three options. The first is to do nothing and let Mac users move to other clients. The second is to re-enable EWS for the whole organization for now. The third is to re-enable it in a controlled way, using the application allow list so that only the applications you trust can use it.

What Microsoft's documentation confirms

• EwsEnabled specifies whether EWS is enabled or disabled for the organization, and accepts true or false.
• EwsApplicationAccessPolicy chooses between EnforceAllowList (only listed applications may use EWS and REST) and EnforceBlockList (everything except the block list may use it).
• EwsAllowList holds the list of allowed client applications when the policy is set to enforce the allow list.
• A separate parameter, EwsAllowedAppIDs, can restrict EWS to specific Entra application IDs.

An example from the Microsoft page, shown here for orientation only, sets the organization to enabled while restricting to named application IDs: Set-OrganizationConfig -EwsEnabled $true -EwsAllowedAppIDs "<app id>". Do not paste commands from articles into a production tenant. Verify the current syntax on Microsoft Learn, test on a pilot group when possible, and record what you changed.

A cautious admin procedure

1. Take inventory. List who uses Apple Mail with the Exchange type. A short email asking staff to check Internet Accounts is usually enough in an office of fewer than 50 people.
2. Read the Message Center. Search for Exchange Web Services and note the dates attached to your tenant. Save a copy for your records.
3. Check the current setting. Connect to Exchange Online PowerShell as a global or Exchange administrator and read the organization configuration. Note the current EWS values before changing anything.
4. Decide scope. Re-enabling EWS for everyone restores the old behavior but also leaves an older protocol available. If you can identify the applications you rely on, prefer the allow list approach so that unknown tools stay blocked.
5. Apply and test with one Mac. Change the setting, wait, and then restart Mail on a test Mac. Changes in Exchange Online can take time to apply, and we could not confirm a specific delay.
6. Write down an end date. Re-enabling EWS is a bridge, not a destination. With a permanent shutdown reported for April 1, 2027, put a migration milestone in the calendar now.
7. Tell staff. Send a short notice with the browser fallback so no one panics if sync lags during the change.

Security thinking for admins

Old protocols are attractive to attackers because they often bypass newer protections such as modern authentication policies and conditional access in awkward ways. That is part of why Microsoft is retiring EWS. If you re-enable it, review sign-in logs for unusual EWS activity, keep multi-factor authentication enforced, and see our guide to setting up two-factor authentication and our article on business email compromise for what attackers do with a stolen mailbox. A pragmatic stance for a small business is: turn EWS back on only if Mac users cannot work otherwise, limit it to the apps you need, and schedule the move to a modern client.

If you are on a Microsoft 365 plan that your reseller manages for you, ask the reseller before touching anything. A partner may already be handling the notice for your tenant. Our overview of Microsoft 365 for Canadian businesses explains how IT Cares supports tenants, licences and email setups.

What if my company runs its own Exchange server?

According to MacRumors, companies that run their own Exchange servers are not affected by this change, because the shutdown applies to Exchange Online, Microsoft's cloud-hosted service. Apple Mail on a Mac connected to an on-premises Exchange server keeps using the same connection it always used.

That said, a few details are worth knowing. Many small companies are hybrid: some mailboxes in the cloud, some on a local server. In a hybrid setup the Mac user's mailbox location decides whether they are affected, not the company as a whole. If you do not know where your mailbox lives, ask your administrator or look at how your colleagues describe it. Outlook on the web will work either way for cloud mailboxes.

The on-premises server is also not forever. Microsoft has its own lifecycle for server products, and many small offices are migrating to the cloud anyway. If you are weighing that move, treat the Mac mail question as one input among others: licensing cost, backup, security, and who will manage the system. Our guide on cloud backup for Canadian businesses covers the backup side of that decision, which is often forgotten.

The key takeaway for on-premises organizations is to confirm, in writing, that your setup is on-premises and not a hybrid mailbox in the cloud. A thirty-second question to your IT provider avoids a Monday-morning surprise.

Migration options: Outlook for Mac, web, or another client

The cleanest long-term choice for a Mac user on Microsoft 365 is Microsoft's own Outlook app, which MacRumors describes as a Graph-compatible client; the web version is the zero-install fallback, and third-party clients are a case-by-case decision because we could not confirm which of them avoid EWS. Apple has said it is working with Microsoft to bring Graph support to Mail in a future macOS update, so staying put is also a legitimate plan, as long as someone owns the risk until that update ships.

If you are choosing for a team, we recommend a simple rule: pick one primary client for everyone, keep Outlook on the web as the universal fallback, and give Apple Mail a time-boxed grace period only if your administrator has chosen to re-enable EWS. Mixed setups create support calls. Three different clients on five Macs means three different sets of settings to troubleshoot.

How to switch from Apple Mail to Outlook for Mac

Install the current Outlook for Mac from your Microsoft 365 account, sign in with your work email, let it download your mailbox, then recreate your signature, rules and calendar view before you remove the account from Apple Mail. Because your mail lives on the Microsoft server, you do not need to export and import messages for a normal cloud mailbox.

1. Update macOS and apps first. Install pending macOS updates. If an update hangs, see our guide to fixing a stuck macOS update.
2. Download Outlook. Sign in to your Microsoft 365 account page with your work address, find the install option for Outlook, and install it. If your plan does not include desktop apps, ask your administrator or check your licence.
3. Add the account. Open Outlook, enter your work email, and complete the Microsoft sign-in including multi-factor authentication. Accept the prompts for notifications and calendar access if you want them.
4. Wait for the first sync. A large mailbox can take a long time on the first run. Leave the Mac plugged in and awake. Do not judge it in the first five minutes.
5. Compare. Open the same folder in Outlook and in the web version. Folder names and message counts should match. If a shared folder is missing, ask your administrator about the permissions.
6. Recreate local items. Mail rules and signatures in Apple Mail are stored on the Mac and do not follow you. Write them down or screenshot them before you remove anything.
7. Set Outlook as the default mail app if you want links to open there: in Mail settings, choose the default email reader.
8. Turn off the old account in Apple Mail only after a week. In Internet Accounts, switch off Mail for the work account rather than deleting it, so you can still read old local copies.

What does not move automatically

• Local-only folders. Apple Mail's "On My Mac" mailboxes are not on the server. Back them up first or drag them into a server folder before leaving.
• Rules and signatures. Recreate in the new client.
• VIP lists and flags. Apple-specific features do not translate one to one.
• Calendar subscriptions. Re-add any non-Microsoft calendars you followed in Apple Calendar.
• Notes and Reminders linked to Exchange. These apps depend on the same connection; export anything important first.

Before you touch local-only data, make a backup. A simple copy of your Mail folder and a Time Machine run is cheap insurance. Our cloud backup guide for Canadian businesses helps you decide where those copies should go.

What about Thunderbird, Spark and other Mac mail apps?

Whether a third-party mail app keeps working depends on how it connects to Microsoft 365: an app that uses EWS is affected like Apple Mail, while an app that uses a Graph-based or other supported connection with modern sign-in may continue to work. We did not open any vendor page for these products, so we cannot tell you which specific apps are safe.

Here is a practical way to find out without reading developer notes. Ask three questions of any mail app you are considering. First, does the vendor's documentation mention Microsoft Graph or "Microsoft 365 modern authentication" for work accounts? Second, does the app say it supports calendar and contacts for Microsoft 365, not only mail? Third, does the vendor have a recent support article about the EWS retirement? If all three answers are yes, test with one user before rolling out to the team.

Be careful with the shortcut of connecting through IMAP. Many administrators disable IMAP or require modern authentication for security reasons, and an app that relies on a basic password may be blocked. It can also give you mail without calendar sync, which solves half the problem. If you are not sure, the simplest answer is the Outlook app or the web version, because they are supported by the same company that is making the change.

Timeline: what happens when

The reported timeline has three milestones: EWS disabled by default in Exchange Online starting October 2026, a permanent shutdown scheduled for April 1, 2027 with no extensions currently planned, and an Apple fix that Apple says is coming in a future macOS update without a date we could confirm. The table separates what we read from what we are inferring.

Two sensible readings follow. For a Mac user, the practical deadline is now, because sync can stop any day. For an administrator, the practical deadline is a few months out, because re-enabling EWS can buy time but not beyond the shutdown date. Anyone telling you the problem will disappear by itself should be asked to show the Apple release notes.

What to tell your staff

Send one short message that says what is happening, what to do today, and who to call, in plain language, without protocol names. Staff do not need to know what EWS stands for; they need to know their email will not silently stop.

Add the date by which you intend to finish. People tolerate change better when they see an end. If you have remote staff, add a line telling them whom to call. For a small office with two or three Macs, a hallway conversation works, but a written note leaves a record if someone misses a meeting because of a calendar problem.

Questions staff will ask

• "Did I lose email?" No. Mail is stored on Microsoft's servers. Sync is what stopped.
• "Is it a virus?" No. Nothing in the reported change points to malware, though you should still be careful with any email asking you to log in again.
• "Can I use my iPhone?" Per MacRumors, yes, the Exchange connection on iPhone and iPad is different and is not affected.
• "Will I need a new Mac?" No. This is a software connection, not a hardware problem.

A related warning to include: attackers like moments of confusion. Expect fake "your mailbox needs to be re-verified" emails. Tell staff that no legitimate fix involves typing a password into a link from an email. Our guide on spotting AI-generated phishing emails is a good reference to share.

Three realistic scenarios (illustrative)

The scenarios below are illustrative examples built from common small-office situations, not real client cases. Names and numbers are invented to show how the decision plays out.

Scenario 1: the solo consultant with one MacBook

A consultant uses Apple Mail with a Microsoft 365 Business account. On Thursday morning new email stops arriving, but the phone still receives everything. She opens Outlook on the web, reads the morning's messages, and then installs the Outlook app on the Mac during lunch. Total time: 45 minutes. Cost: nothing beyond her existing licence. She keeps Apple Mail's Exchange account switched off but not deleted for a week.

Scenario 2: the 12-person design studio with 8 Macs

The studio owner is also the administrator. Calendars drive client meetings, so a missed invitation is expensive. She checks the Message Center, reads the Microsoft documentation for the organization-level setting, and re-enables EWS with an allow list, then tests on one Mac. She schedules the Outlook rollout for two Fridays in November, two Macs at a time, and sends the staff notice above. Result: no lost meetings, a dated plan, and no panic in January.

Scenario 3: the 5-person accounting office with a mixed fleet

Four staff use Windows with Outlook; the bookkeeper uses a Mac with Apple Mail. Only she is affected. The owner does not want to change a tenant setting for one person. Instead the bookkeeper moves to the Outlook app on the Mac, and the owner asks the IT provider for a one-hour remote session to recreate the signature and rules. Cost: one Expert Consultation, 119.99$ CAD for 60 minutes, as a reasonable ceiling for an office this size.

The common thread is that the cheapest answer is the one chosen before the deadline, not after a client email goes unanswered for three days.

What it costs: doing it yourself versus getting help

For one Mac, the do-it-yourself path costs nothing if your Microsoft 365 plan already includes the desktop Outlook app, and about 45 to 60 minutes of your time; paid help makes sense for teams, for admin changes you are not sure about, or when email is business critical. The numbers below are estimates for planning, not quotes.

Taxes (GST and QST in Quebec) apply on top. We deliberately do not quote Microsoft licence prices, because they change and vary by plan; look at your own admin center. The real cost of ignoring the change is usually a missed message, which is hard to price but easy to imagine.

If it is not EWS: other reasons Apple Mail stops syncing

Not every Apple Mail sync failure is the EWS change: expired passwords, changed multi-factor settings, offline mailboxes, full disks and damaged local mail data produce nearly identical symptoms, and you should rule them out in a fixed order before blaming Microsoft. A browser test is the dividing line: if Outlook on the web fails too, the account is the problem; if it works, the connection from your Mac is the problem.

Local fixes worth trying (only if the browser works)

1. Restart Mail and the Mac. It sounds basic, but a stuck sync process is common after a macOS update.
2. Check free disk space. If the Mac has under a few gigabytes free, Mail cannot download. Free some space before anything else.
3. Toggle the account off and on. In Internet Accounts, switch Mail off for the work account, wait ten seconds, switch it on again. This keeps the account but forces a reconnect.
4. Take Mail offline and back online. In the Mailbox menu use Take All Accounts Offline, then Get All New Mail.
5. Test a second macOS user. Create a temporary user, add the account there. If it fails there too, the account or server is the cause, not your profile.

If these steps do not help and the browser works, the most probable explanation is the server-side switch, and the answer is a decision by the administrator, not another round of resets. Resist the temptation to delete mail databases or reset system files on your own; if the real cause is server-side, those steps cost you time and possibly data.

Security and privacy during the switch

Treat the transition as a chance to tighten email security: confirm multi-factor authentication is on, avoid insecure shortcuts like forwarding to personal inboxes, and expect scam emails that exploit the confusion. Email is the key to every other account, because password resets go there.

• Multi-factor authentication. If it is not enforced on your tenant, do it this month. See our guide to setting up two-factor authentication.
• Password manager. A manager makes re-entering credentials safe. Our business password manager guide compares options.
• Phishing. Scammers send fake "mailbox sync problem" messages with login links. Real fixes never ask for your password by email.
• If an account is compromised, follow our email account recovery guide and tell your administrator immediately.

For Quebec businesses, remember that personal information in email, such as client names, health or financial details, falls under Law 25 obligations. If a forwarding rule or a poorly chosen workaround sends company mail to a personal address, that can become a privacy incident. Keep the workaround inside the company tenant.

Official resources

For authoritative answers, rely on Microsoft's documentation for the admin settings, on the Message Center in your own tenant for dates that apply to you, and on Apple's release notes for any Mail update. The pages we actually opened for this article are listed in the Sources block at the end.

• Microsoft Learn, Set-OrganizationConfig (EwsEnabled, EwsAllowList and related parameters): learn.microsoft.com
• MacRumors report, October 1, 2026: macrumors.com
• Your Microsoft 365 admin center, Message Center: search for Exchange Web Services (sign-in required).
• Apple Support and macOS release notes: check for any note about Microsoft Graph support in Mail (we did not open an Apple page).

When to call a professional

Call for help if you manage more than a handful of Macs, if you are unsure about changing tenant-level settings, if your email is business critical, or if you suspect the account has been compromised. A short remote session often settles in an hour what a person could spend an afternoon guessing at.

IT Cares has provided remote and on-site IT support in Quebec and across Canada since 2014. We can review your Microsoft 365 setup, advise whether to re-enable EWS temporarily, move Mac users to Outlook or another client, recreate signatures and rules, and write the staff notice. If you only need one Mac sorted, a single 60-minute Expert Consultation at 119.99$ CAD is usually enough.

Call 1 (888) 711-9428 or book a remote session. If you can, tell us your macOS version, whether the account type shows Exchange in Internet Accounts, and whether Outlook on the web works. With those three facts, we can usually tell you the cause within minutes.

Frequently asked questions

Related guides

• Fix Outlook not working
• Recover a hacked Outlook account
• Set up two-factor authentication
• Business email compromise protection
• Fix a stuck macOS update
• Cloud backup for Canadian businesses
• Spot AI-generated phishing emails
• Business password manager guide
• Microsoft 365 for Canadian businesses
• Email account hacked recovery

Sources and official references

Last verified: October 1, 2026

• MacRumors: Apple Mail on Mac may stop syncing Microsoft 365 accounts (Oct 1, 2026)
• Microsoft Learn: Set-OrganizationConfig (EwsEnabled, EwsAllowList, EwsApplicationAccessPolicy)