Microsoft 365 stopped working

Question

I started using Microsoft 365 just last month on my old MacOS Catalina, version 10.15.7. Tech support had to kinda rig 365 so I could use it. Today it stopped working. And trying to get tech support is impossible.

Can anyone help? How can I get to the proper support tech?

Someone here gave me great advice about needing to rig for my old Mac.

Answer 1

Hello Sudi Scott, thanks for posting this in the community.

Microsoft 365 apps no longer support macOS Catalina, and the last version compatible with Catalina has already reached the end of updates. If your Office apps were manually configured to work on this older system, they can stop launching once the support files or activation services fail. The best step is to update your Mac to at least macOS Big Sur or newer so you can install the current supported versions of Microsoft 365. If your device cannot upgrade, you can use Office for the Web through www.office.com as a temporary option.

 

Kind regards,

John Oli

Answer 2

Microsoft 365 is no longer supported on macOS Catalina, so apps can stop working and built‑in support options may fail or be limited.

To get things working as reliably as possible on an older Mac and reach the right support options, use these steps:

1. Confirm macOS and Office support status
   • Microsoft 365 for Mac only supports the three most recent major versions of macOS. Older versions (like Catalina) are out of support.
   • On an unsupported macOS, Office apps may still run, but they no longer receive updates or security fixes and some features (including certain support flows) may not work as expected.
   • Details are in Upgrade macOS to continue receiving Microsoft 365 and Office for Mac updates.
2. Use the most recent Office build that still works on older macOS
   • For older macOS versions, the practical fix is usually to install the last Office build that supports that OS, then keep it at that version.
   • The “Most Recent Office You Can Run – Best Practices” guidance (referenced in multiple Q&A answers) explains that for older macOS versions you must install a specific final build (for example, Monterey is limited to 16.89 as of September 10, 2024). Catalina similarly requires an older, fixed build.
   • If Microsoft 365 recently updated itself beyond what Catalina can reliably run, uninstalling and reinstalling the appropriate older build is often required.
3. Fully remove and reinstall Office for Mac If the apps suddenly stopped working or crash, a clean reinstall is recommended:
   1. Quit all Office apps.
   2. In Finder > Applications, select all Microsoft 365 apps (Word, Excel, PowerPoint, Outlook, OneNote) and move them to Trash.
   3. In Finder, select Go > Go to Folder and open:
      • ~/Library/Containers/
      • Delete folders starting with:
        • com.microsoft.Word
        • com.microsoft.Excel
        • com.microsoft.Powerpoint
        • com.microsoft.Outlook
        • com.microsoft.OneNote
      • Go back to ~/Library and open Group Containers and move these (if present) to Trash:
        • UBF8T346G9.ms
        • UBF8T346G9.Office
   4. Empty Trash.
   5. Sign in to https://account.microsoft.com/services and reinstall Office for Mac from there.
   6. After install, run Help > Check for Updates once to ensure you are on the final supported build for your OS, then turn off automatic updates if a newer build would require a newer macOS.
4. Contact Microsoft support outside the Mac app Since in‑app support can fail on unsupported macOS, use the general support channels instead:
   • For home subscriptions (Microsoft 365 Personal/Family/Premium), technical support is available via chat or call back from a support expert. Start from the Microsoft 365 support contact page referenced in Microsoft 365 Customer Service and Support.
   • Another route is described in Contact Microsoft Office Support:
     1. Search online help.
     2. Ask the Microsoft Community.
     3. Use the Get Help app or browser to contact support.
5. Consider updating macOS if possible
   • To restore full support (including updates and in‑app support flows like Outlook’s Contact Support), upgrading to a supported macOS version is strongly recommended if the Mac hardware allows it.
   • On unsupported macOS, Office will continue to be “best effort” only, with no guarantee that future sign‑in, activation, or app behavior will remain stable.

If Catalina cannot be upgraded further, the stable long‑term approach is to:

• Install and keep the last Office build that supports Catalina.
• Disable automatic Office updates.
• Use web versions of Word/Excel/Outlook in a browser when possible for newer features and security.

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References:

• Upgrade macOS to continue receiving Microsoft 365 and Office for Mac updates
• Microsoft 365 Customer Service and Support
• Contact Microsoft Office Support
• What to try if you can't install or activate Office for Mac
• Microsoft Office apps for Mac quit unexpectedly - Microsoft Q&A
• Office running on OS 12.7.6 - Microsoft Q&A
• Help! I can't get 365 to work. Can I use it on my MacOS or do I need Office? - Microsoft Q&A
• Can't access Microsoft support - Microsoft Q&A