A user reported an install problem. I asked them to start setup from the command line with the verbose logging option, and this seems to be where the problem is:
DIFXAPP: INFO: ENTER: DriverPackageInstallW
DIFXAPP: INFO: RETURN: DriverPackageInstallW (0xE0000247)
DIFXAPP: ERROR: encountered while installing driver package 'C:\Program Files\AcmeWidgets\WidgetApp\widget-driver.inf'
DIFXAPP: ERROR: InstallDriverPackages failed with error 0xE0000247
DIFXAPP: RETURN: InstallDriverPackages() 3758096967 (0xE0000247)
CustomAction MsiInstallDrivers returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)
Action ended 21:00:47: InstallFinalize. Return value 3.
MSI (s) (50:CC) [...]: Note: 1: 2265 2: 3: -2147287035
Our driver is signed (Digicert EV Code Signing Certificate), and our Windows 10 and other Windows 11 users are able to install the app with no apparent issues.
Could this be a known issue with Windows 11 Insider Preview?