Could Not Validate version 15.21.0 of butler on macOS

[Geordon]

When installing butler on a current release of macOS, the default SIP will not allow the program to run due to not being signed. In order to get it to run the sanity check, you will have to manually go to the location in Finder (/Users/$USERID/Library/Application Support/itch/broth/butler/versions) and right click/command-click then OPEN the butler executable in order to get macOS to ask you if you're sure you want to run the unsigned executable even though macOS can't check it for malicious software.

[OlliHolli]

I'm having the same issue on Windows.
I already disabled my antivirus software, but it didn't help.
Anything I can do?

[diveonebot]

I'm running windows 11 and Butler nor the Itch.io app will install. The butler install fails silently so I can't see teh logs. Itch app gives the error explained in this issue. First it throws ENOENT on the sanity check because it can't find butler installed. Then I get Error: Could not validate version 15.21.0 of butler.

Any idea why butler is failing silently on install?