Dealing with sign-in snafus in Microsoft 365 or Office apps is kind of frustrating, especially when cached data or leftover credentials cause conflicts. Sometimes, it’s those old login details stored somewhere that mess everything up, making you go in circles. Other times, Windows or Office might be confused about which account to use, especially if multiple work or school accounts are linked. Fixing this stuff often requires a mix of clearing caches, disconnecting accounts, or refreshing licenses. The goal here isn’t just to fix the sign-in issue but to also head off similar hiccups in the future. If you’re tired of getting stuck on these errors, this guide covers a few practical ways to clear out the junk and get Office to play nice again. Spoiler: it can be a bit flaky, and sometimes you need to try more than one fix.
How to Fix Microsoft 365 Sign-In Problems
Sign Out of All Office Applications and Sign In Again
This method is good if Office apps are acting weird because of cached credentials or multiple accounts trying to sign in at once. Clearing out stored login info forces Office to ask for fresh credentials, which can resolve conflicts. Usually, this fix works when you see errors popping up during sign-in or when credentials randomly get “stuck.”
- Open any Office app like Word or Excel.
- Click your profile picture in the top right corner.
- Choose Sign Out and confirm. For some reason, on certain setups, this can actually be a bit stubborn, so make sure it signs out completely.
- Repeat for all accounts, if multiple are signed in.
- Close all Office apps, then restart your computer — because of course, Windows has to make it harder than necessary.
- Reopen the same Office app, click Sign In at the top right, and enter your account details. Make sure you’re only signing in with your primary work or school account if that’s what you use.
- Go to File, then Account — on some versions, it might be labeled as Office Account. Check to see if only your intended account is listed under Connected Services or User Information.
- If it still acts up, try using the Credential Manager.
To clean credentials, just search for Credential Manager in the Windows search bar, go to Windows Credentials, look for anything related to Office, Microsoft, or your account, and delete those entries. After that, restart your PC and see if it helps. Seriously, sometimes this is the magic move.
Disconnect Work or School Accounts
If you have multiple work or school accounts linked and it’s causing confusion — like, which one is supposed to be signed in — removing the extra ones can help clear up sign-in issues. This is especially true if new account setups or account switches have caused weird behaviors.
- Press Windows + I to open Settings.
- Go to Accounts, then select Access work or school.
- Find the account you no longer need or that might be causing the conflict.
- Select it and click Disconnect. Confirm if prompted.
- Reboot your machine to make sure it refreshes the account list.
This isn’t guaranteed to fix every sign-in problem, but it quite often clears up account conflicts that cause those stubborn errors.
Clear Office License Activation Data
Sometimes, Office gets confused because the activation files are corrupted or outdated. Deleting these files forces Office to fetch new activation info, which can fix licensing or sign-in errors, especially after Office updates or account switches.
- Close all Office apps like Word, Excel, PowerPoint, etc.
- Press Windows + R, type in the path:
%localappdata%\Microsoft\Office\16.0\Licensing - Press Enter and open up that folder.
- Select all files inside and delete them. Sometimes, this step is a little nerve-wracking because you’re deleting system-specific licensing files, but it’s safe in this case.
- Reboot your PC — yeah, again, rebooting is often the simplest patch.
- Open an Office app and sign in with your usual account. Office will regenerate the license info.
- Check if the sign-in error is gone.
On some setups, removing these files can be a bit hit-or-miss, but it’s worth a shot if licensing took a hit.
Use the Microsoft Support and Recovery Assistant (SaRA)
This is kind of a lifesaver when things get weird. SaRA is a free, official tool from Microsoft that scans your Office installation, accounts, and licensing, then repairs what it finds. Usually works well because it’s designed specifically for these issues and guides you through troubleshooting, step by step.
- Head over to the Microsoft Support and Recovery Assistant download page.
- Download and run SaraSetup.exe—the installer might seem a bit basic, but don’t skip it.
- Once installed, launch the tool and pick Office & Office Apps.
- Select I am unable to sign in to activate or use Office apps and start the scan.
- Follow the prompts. It’ll check your account, licensing, and connection issues. Sometimes it fixes everything automatically; other times, it just points you to the next step.
- When it’s done, try signing in again and see if the errors are gone.
This tool’s kind of a one-stop shop for stubborn Office sign-ins, and it’s kept updated to handle the most common problems. Not every problem, but a major help in many cases.
Summary
- Sign out of all Office apps, then sign in fresh.
- Remove stored credentials via Credential Manager.
- If applicable, disconnect unnecessary work or school accounts.
- Clear Office licensing files and restart.
- Run SaRA for a quick scan and automatic fixes.
Wrap-up
Getting Office sign-in to behave again can feel like chasing your tail, but these methods cover the most common culprits. Usually, starting with signing out and clearing credentials is enough, but if that doesn’t stick, the license reset or SaRA should do the trick. Sometimes, it’s just a matter of patience — and plenty of reboots. Hopefully, this shaves a few hours off someone’s troubleshooting marathon. Good luck, and may your Office apps stay signed in!