1Password installed on non system (C:) drive silently breaks passkeys (and more)

If Windows is configured to install new apps on a secondary drive/partition, 1Password will be installed there instead of C:, when using the MSIX installer. This silently breaks some things. Passkey support is completely not working, nowhere to be found, without any hint. Also the option to switch release channel and to check for updates are missing.

How to fix and get passkeys working: 

1. Uninstall 1Password and reboot
2. Go to Windows settings > System > Storage > Advanced storage settings > Where new content is saved and change "New apps will save to:" To: "Windows (C:)"
3. Install 1Password using the MSIX installer and launch
4. (Optional) Change "New apps will save to:" back to the preferred partition

After the reinstall I immediately got the passkey popup in 1Password.

My Suggestion:

When 1Password is not installed on the system drive, there should be a hint, that some things might not be working. Also I think the Autofill section should not be hidden completely, but display a warning like "For Passkey support, 1Password must be installed on system (C:) drive".

Otherwise, it is really difficult to figure out this issue, since everything else is working perfectly fine. Even adding additional trusted browsers works, which requires the browser to be installed on the system drive.

I've been using passkeys on my laptop for months and just now figured out, why it wasn't working on my PC. I have tried so many things and reinstalled 1Password more than once, before finding the actual cause. I thought windows was just bad and not enabling the feature or something.