Processes in Microsoft 365 Insider for installing preview builds, activating subscriptions, and keeping apps up to date with the latest Insider features.
Hi
It looks like something might have gone wrong with the installation.
Let's test.
Go to the Applications folder. Drag Microsoft Outlook.app to the trash
Download and then run the 16.45 installer Install package
Restart your Mac
Now see if this version runs. If it does, then use Help > Check for Updates to get the 16.46 build.
If it were me, before doing anything I would give the file system a quick check