Outlook Unknown Error

Wojciech Mazurek 20 Reputation points
2026-08-02T13:19:43.7+00:00

I have the desktop version of Outlook. When I try to activate Outlook, I get the error "Unknown Error" — "An unknown error occurred." The error code is 0x0". Outlook is version 16.79.1 (23111614) running on macOS Monterey. Everything worked correctly until I had to renew my Office 365 subscription and activate Outlook again.

Microsoft 365 and Office | Subscription, account, billing | For home | MacOS
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Answer accepted by question author
DaveM121 931.9K Reputation points Independent Advisor
2026-08-02T13:59:27.74+00:00

Many people are reporting that 0x0 error with the Office apps on a Mac after the July 13 update, if you have MacOS Monterey (12.7.6), you will first need to uninstall Office from your Mac, then install the last version of Office that will work on MacOS Monterey (16.88), that is available on the long table on this link to all the downloadable versions from the Microsoft servers.

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

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