Forum Discussion
Activation failed
I have been running MS 365 on my Mac laptop for years with no issue. Suddenly I cannot save an Excel file. I saw the activation button, but activation failed with the code OxO....unknown cause. I cannot find any way to contact MS for support or chat. I checked on my desktop and I do have an active subscription. I am running Tahoe 26.5.2. Excel is 16.7.1. Any suggesstions.
9 Replies
I have same issue. I am running macOS 12.1, but I search and find this OS is okay for Excel, anyway I have not fixed this problem.
Hi have you resolved this ? My Wife rebooted her Macbook 2 days ago and 365 (2019 for Mac) seems to have updated itself and lost activation giving the same 0x0 Error. There is a valid licence showing in My accounts. I have reinstalled multiple times and run Licence Tool - I sent 90 minutes on phone to support just to reinstall again under their guidance and eventually be told to go buy a licence for a newer version as it is out of support !
Where you able to fix this? Had the exact same issue
Got it. Did a reinstall and all is well.
Hi Jon, I have exactly the same issue as you did. I reinstalled excel but no luck on my end. What version of excell are you running now? is it newer then 16.110..
Did your reinstall work ? I have same problem and multiple reinstalls and licence tool runs have not worked - Over an hour with support resulted in them telling me to buy a new Licence ! Despite having a perpetual licence for 2019 for Mac. cheers Bob
Hi JonHunt,
Error code 0x0 is a bit unusual because it generally indicates the activation process didn't return a specific error, making it more of a generic activation failure than a licensing issue.
A few things I'd try:
- Sign out and back into Microsoft 365 from any Office application (Excel > Account or Help > Sign Out), then restart Excel.
- Open the Microsoft AutoUpdate app and make sure both Office and AutoUpdate are fully up to date.
- Confirm your Mac's date, time, and time zone are set automatically, as incorrect system time can interfere with license validation.
- If you're signed into multiple Microsoft accounts (personal, work, or school), make sure Excel is using the account that owns the active Microsoft 365 subscription.
- If the issue started after an update, try removing the Office license credentials from macOS Keychain Access (look for Microsoft Office or ADAL/MSAL entries), then sign in again to refresh the activation token.
Since you mentioned your desktop still shows an active subscription, the subscription itself is probably fine. This sounds more like a local activation cache or credential issue on the Mac.
This matches the Microsoft 365 for Mac licensing-certificate change that took effect on July 13, 2026. Older Office builds enter reduced-functionality mode, so they can open files but cannot edit or save. Excel 16.7.1 is well below the required current build.
In Excel, choose Help > Check for Updates, select Update All, and update to version 16.110 or later. If Office came from the Mac App Store, update it there instead. Quit and reopen all Office apps, then sign in with the account that owns the active subscription.
If AutoUpdate is missing or will not update, reinstall Microsoft AutoUpdate (or reinstall Microsoft 365 from your account) and try again. Only if activation still fails after updating, run Microsoft's Office License Removal Tool and reactivate.
Thanks...update did not work, but I am trying to reinstall 365.
