Whenever I try to install the Itch Windows app, I get this screen.

 There was a problem during setup: Could not validate version 1.15.0 of itch-setup

When looking through the logs, I get a lot of "sanity check failed."

I don't use any antivirus, and Windows Defender's realtime protection was disabled while installing.

What can I do to install the app?

Same things happened to me, and the problem is same by the way. But the different is, I passed that one and got another problem after that

No Antivirus, Windows Defender was set up for whitelist some directories, but the app shows this:

And the log:

And the problem keeps showing after re-installing the itch app :(

Getting this same exact bug right now. Uninstalled, still no dice after a fresh reinstall.

In my case the installer simply does nothing.  No errors.  Nothing.

It's fixed for me now, I was finally able to install the itch app

I resolved my issue by adding an exception
A) 1) for the itch installer and
A) 2) afterwards the installed itch app
B) to my Windows 10 Controlled Folder Access / Anti Ransomeware
Guide: https://www.windowscentral.com/how-allow-blocked-apps-ransomware-protection-wind...