Error 0x0 when I attempt to sign in.

Question

The title pretty much describes the problem.

Although I paid for this copy of Office (MacOS), and have been using it without a problem, I am now prompted to "activate" it. When I attempt that, I get a box with the following.

"Unknown Error

An unknown error has occurred. The error code is: 0x0"

Microsoft Excel for Mac

Version 16.66 (22100900)

When I described the problem in MS's support site, I saw links to three other similar questions. Unfortunately, none of those questions were close enough to mine to provide useful information.

Answer 1

If your OS is above version 12 but below 14, your office products can be functional, but Microsoft no longer maintains or updates that version. In this scenario, you can install the older downgraded version.

However, if it is below 12, it will now enter reduced functionality mode. In another word, the OS is too old to receive the licensing update the Office now requires. Sorry. Buying new Office will not help. It is the MacOS being the problem, not office.

Answer 2

Hello robert sheehan,

I understand that your Office for Mac is now unexpectedly prompting for activation, and Excel version 16.66 shows “Unknown Error – error code: 0x0” when you try to activate it.

I’ve noticed a few similar reports recently. I’m not aware of a confirmed fix at this point, but the following steps may be worth trying:

First, please quit all Office apps and run Microsoft’s official Office license removal tool. This clears potentially damaged or outdated licensing information stored on the Mac. Then reopen Excel and sign in with the Microsoft account associated with the Office purchase.

Note: The license removal tool only clears saved activation/licensing data on your Mac, it does not delete your purchase or invalidate your license. However, please make sure you still have access to the correct Microsoft account associated with your original Office purchase, as you will need to sign in again to reactivate it after running the tool.

If the issue continues, uninstall Office and reinstall another release, such as version 16.110.2, from the official Office for Mac update history as a temporary workaround.

Hope this could help. Please let me know how it goes!

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