Thanks, just a warning to those Mac using MacOS Catalina and unable to upgrade to Big Sur (which requires 35 GB of extra hard drive space): do not update your Outlook to 16.64, it just doesn't work under Catalina - crashes at startup.
The solution for us has to be what BJ Scheid proposed (enter defaults write com.microsoft.Outlook DisableSignatures 0 in the Terminal).
It certainly does work in Catalina. Checkout the screenshot (removed personal info)
You need 35GB to upgrade macOS to Bir Sur (which is not a requirement to instal Outlook v16.64) becuase the downloaded installer file and the installation require additional working space. Catalina requires 12.5GB to upgrade so it's a net difference increase of 22.5GB after the installation is complete, which is far less than 35GB. To reduce the space needed to install you can run the 5GB installer from a USB flash drive.
macOS Big Sur - Technical Specifications
https://support.apple.com/kb/sp833?locale=en_US
macOS Catalina - Technical Specifications
https://support.apple.com/kb/sp803?locale=en_US&viewlocale=en_US
The "DisableSignatures" almost always fails after of couple of reboots. This is true on Monterey (12.5.1) and Catalina (10.15.7).
