wait, how did you manage to post this?

You shouldn’t download butler manually to run the itch.io app, the app will download and install its own copy butler to the correct place automatically. The issue you are most likely experiencing is described in the error message you pasted: Antivirus software may interfere with itch.

There’s some third party software on your computer that is altering or blocking the automated installation of butler. Try temporarily turning off your virus/malware/firewall software and try again to see if it solves the issue. If it does, then you know the source of your problems.

Thanks

(I said turn off intentionally – trying to add an exception is easy to do wrong, so save yourself the trouble and fully disable it for this test)