Hello Paul,
I'm Diane, a Microsoft 365 Apps & Services MVP and I'll try to help you today.
I have not seen that error in years- it is a corrupt installer error. There is a setup.exe for what's app and teams installer tries to use it.
In downloads: do you have a setup.exe? Rename or delete it.
You can try clearing everything from the temp folder too -Teams should extract the files in the temp folder, if they are not deleted when it finishes or fails, you can run the setup.exe from there.
(C:\Users%username%\AppData\Local\Temp)
I explain the error in this article -
https://www.slipstick.com/outlook-bcm/bcm-insta...
-- Diane
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