Updater.app is damaged and can't be opened. You should move it to the Trash

When I got the "is damaged and can't be opened. You should move it to the Trash" error, it was a tiny text file I put extremely important login information in. I knew it was not malware, was extremely unlikely to have actually been corrupted and this was most likely another idiotic Apple message that was just wrong - this one helpfully suggesting I destroy data, so I dug in a bit deeper and found this message can simply mean it has the "com.apple.quarantine" extended attribute set.

Shame on you Apple. You are telling users to delete files because they have an extended attribute - most likely set in error but your own OS. At least throw the full path with this error. Pull your head out.

Anyway, you will need to use the command line to do this: I like iTerm but the preinstalled Terminal app will also work, whatever. The key point is you can use this extended attribute flag to locate the app throwing this error. Depending on how many apps you have installed, the find command can run for a long time:

Look for every file named "Updater.app" and ignore any permissions errors, then redirect the list to a file:

find / -name Updater.app 2> /dev/null > files_Updater.app_list

Scrape through the list and look for files with the com.apple.quarantine extended attribute:

for i in $(cat files_Updater.app_list) ; do echo $i ; xattr $i ; done

This will print all the found files. If the extended attribute is found in any of them, it will print "com.apple.quarantine" after the filename.

The path to the file will tell you which app is throwing the error.

Good luck!

Unfortunately, many applications have a separate Updater.app file they use for updating their own apps. It might be worth the effort to open (one by one) all your apps (except Apple apps) and see if any complain about not being compatible with your version of macOS. Then once found, you can remove that app, and then get the most recent version of it and install that. I'm not aware of any tricky way to isolate which one it is accept as I indicated. If any other contributors here know of a way, would like to read your input.