Unable to active Microsoft Excel

Question

• Macbook air early 2015
• macOS Monterey 12.7.6 Office version 16.78(23100802).
• Microsoft 365 subscription is active
• Office 2019 licences removed with License removal tool.
• Can sign into microsoft account in Safari.
• When clicking activate in excel or word
• sign-in starts but immediately returns "Unknown error 0x0 and "Unable to Activate Microsoft 365" before password entry.
• I cannot edit or create in excel.

Answer 1

If your version of MacOS is Monterey, then the error you are seeing is caused by an update on the 13th of July, many people are seeing the exact same error (0x0), if you are unable to upgrade your MacOS to a newer compatible version, your Office apps will go into Read Only mode, on the link below the full details on that update are provided.

https://support.microsoft.com/office/update-microsoft-365-or-office-on-your-macos-or-ios-device-f418ae5d-bb5f-4078-b3d9-9340f5dd084e

If you are unable to upgrade your version of MacOS 12.7.6 (Monterey) to a more up to date version.

The last version of Office that will work on MacOS 12.7.6 (Monterey) is 16.88, that is available on the long table on this link to all the downloadable versions from the Microsoft servers, you will need to completely uninstall the Office apps from your Apple Mac first before installing that version.

https://learn.microsoft.com/en-us/officeupdates/update-history-office-for-mac