Problem changing login using Office 365 (macOS 10)

Question

Problem changing login using Office 365 (macOS 10)

Startingtopuff 0

I have recently uninstalled Office 365 from a MacBook 10.13.6 High Sierra and reinstalled Version 16.43 as part of a troubleshooting problem with Word. When I try to activate using my new 365 Family subscription details it hangs 'Loading' and however long I wait it doesn't complete. If I use an old Office 365 login from when I used it in a college everything works fine. I have run the licence removal tool but to no avail. How can I get through this problem? Thanks in advance.

Moderator note: Locking thread—information from 2025 with regards to running older versions of Office on a Mac is no longer correct as of July 2026. Anyone who has further questions can start a new thread via the Ask a question option.

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3 answers

Answer 1

John Tudor 0

I realise this is a bit old now.
Are you able to send me the direct link for the last supported installer for my MacBook running High Sierra please.

Stefan Blom 353.7K Reputation points MVP Volunteer Moderator

2026-08-12T09:34:31.1266667+00:00

I realise this is a bit old now. Are you able to send me the direct link for the last supported installer for my MacBook running High Sierra please.

@John Tudor

I'm afraid a lot has changed since last year regarding Office licensing on a Mac. You won't be able to run Office at all on older Macs. You need macOS 12 or later and you need an Office license which lets you install Office release 16.83 or later. See John Korchok's article at https://www.brandwares.com/bestpractices/2023/03/most-recent-office-you-can-run-best-practices/ (updated 2026) and the support article at https://support.microsoft.com/en-us/office/lifecycle/officeinstall/update-m365-office-macos-ios .

If you can't upgrade your operating system right now, or if you don't want to, what you can do is run the web browser versions of Word, Excel, PowerPoint, and Outlook, or you can try an open source alternative such as LibreOffice.

If you have further questions for your fellow users here in Q&A, I recommend that you start your own thread. Use the Ask a question option next to your avatar at the top of the Q&A page or click the menu icon and then click Ask a question.

Good luck.

The current thread is old and it will be closed.

Answer 2

Hi, I get how confusing that can be when everything looks fine but the sign-in just spins.

The main issue here is that macOS High Sierra is pretty old, and Microsoft stopped supporting it for newer Office builds.

Even though you installed version 16.43, the login process uses modern web components that High Sierra struggles with, so it never completes.

Here’s what I’d try first: make sure you’re really on 16.43, then run the license removal tool again and manually clear any leftover files in /Library/Group Containers/UBF8T346G9.Office and any Microsoft items in Keychain.

Restart, then open Word and sign in using “Sign in with another account.”

If it still hangs, try logging into your Microsoft account in Safari first, then retry in Word.

Quick question, are you okay keeping AutoUpdate set to manual, so it doesn’t push newer versions that won’t work on High Sierra?

And do you want me to send you the direct download link for the last supported installer?

Regards,
Aron

Startingtopuff 0 Reputation points

2025-11-19T13:58:13.4866667+00:00

Hi Aron and thank you for your advice. I have taken all this on board but unfortunately it was to no avail. I then decided to adopt a nuclear approach and formatted drive, did a clean install High Sierra from USB boot disk, and installed Office 16.43. This didn't work and I experienced the same symptoms but at least it discounted any orphan files. This morning I had a eureka idea and used the original college credentials and it worked. I think this means there isn't an issue with the High Sierra and Office 16.43 pairing and has to be down to an activation problem with my new Office 365 account. I can access my Microsoft account via web browser and my iMac, Macbook Air and Lenovo Desktop running Windows 11 so the subscription is working on everything except my Macbook Pro. Its a pity the web portal doesn't show devices.

Answer 3

It sounds like you're experiencing issues with activating Office 365 on your Mac after reinstalling it. Here are some troubleshooting steps you can try:

Ensure you are signed in with the correct account: Make sure you are using your new Microsoft 365 Family subscription account to sign in. Sometimes, using an old account can cause conflicts.
Sign out and sign back in: Open any Office app (like Word), select your name or profile picture at the top, sign out, and then sign back in with your new account.
Check for any updates: Make sure that your Office installation is up to date. You can check for updates in any Office app under Help > Check for Updates.
Use the Mac License removal tool again: Since you mentioned you ran the license removal tool, ensure that you followed the instructions correctly. You can refer to the guide on how to remove Office license files on a Mac for detailed steps.
Uninstall and reinstall Office again: If the problem persists, consider uninstalling Office completely and then reinstalling it. You can follow the instructions for uninstalling Office for Mac and then reinstall it from your Microsoft account.
Try InPrivate or Incognito mode: If you're accessing the activation page through a browser, try using InPrivate mode (Microsoft Edge) or Incognito mode (Google Chrome) to see if that resolves the loading issue.

If none of these steps work, you may want to contact Microsoft support for further assistance.

References: