Word, Excel or Outlook on a Mac asks you to sign in, you type your password, it accepts it, and ten minutes later it asks again. Sometimes the box will not accept the password at all. This is one of the most common Mac problems we see and it is almost always fixable.

Try this first

1. Sign out of every Office app, not just the one that is nagging. Office apps share one sign-in between them, so signing out of Word while Outlook is still signed in changes nothing. Open Word, click Word in the menu bar at the top of the screen, then Sign Out. Do the same in Excel, PowerPoint and Outlook.
2. Quit everything properly. Closing the window is not the same as quitting on a Mac. Press Command and Q in each app, or right-click the icon in the dock and choose Quit. Include Teams and OneDrive.
3. Restart the Mac. Click the Apple menu, then Restart.
4. Open Word and sign in once with your work email address. When it asks whether to allow it to manage the account or to remember it, say yes. Then open Outlook and check whether it asks again.
5. Check there is only one work account. In Outlook, click Outlook in the menu bar, then Settings, then Accounts. If an old employer's account, or the same address listed twice, is in there, that is very likely your problem. Tell us what you see rather than deleting anything, because removing the wrong one can take local mail with it.
6. Check for updates. Open any Office app, click Help in the menu bar, then Check for Updates, and install everything offered. Then check macOS itself under the Apple menu, System Settings, General, Software Update. Sign-in loops on Macs are frequently an old version arguing with a newer security requirement.

If that didn't fix it

If the prompt keeps coming back after all of that, the cause is usually one of two things and both need a hand.

The keychain. The keychain is the Mac's built-in password store. Office keeps its sign-in tokens there, and when those entries get damaged or duplicated, Office cannot read its own saved sign-in and asks again every time. Clearing the right entries fixes it in minutes. Clearing the wrong ones can lock you out of wifi, other apps and saved passwords across the whole machine, so please do not go digging in Keychain Access on your own. Ask us and we will do it with the machine in front of us.

The licence. If the account has no Microsoft 365 licence assigned, or the licence was recently moved, Office will keep asking as though it is a password problem when it is not. We can check that from our end in a minute or two. If you are also seeing a banner about an expired subscription, that is the same underlying cause.

When you log the ticket, tell us:

• Which apps ask, and whether it is all of them or only Outlook.
• The exact wording of the prompt, and a screenshot if you can. Press Shift, Command and 4, then drag over the box.
• Whether you have ever used this Mac with a different work account, or whether it came from a previous job.
• Whether signing in at outlook.office.com in Safari works normally.
• Your macOS version, from the Apple menu then About This Mac.

Why this happens

Macs are perfectly good business machines, but Office on a Mac keeps its sign-in in the keychain rather than inside Windows where it is more tightly integrated. That extra step is the weak point. Add a Mac that has carried more than one work account over its life, or one that has skipped several updates, and the sign-in loop is the usual result. Nothing here is a sign that anything is wrong with your account or your mail.

Still stuck?

Log a ticket at portal.yougrowit.com.au or email support@yougrowit.com.au. If it is stopping you working right now, call 03 9028 4358.

Support hours are Monday to Friday, 8:30am to 5:30pm Melbourne time, excluding Victorian public holidays.