I just downloaded Parallels (see below for version info) onto my MacBook running Mac OS X 10.13.6 (17G65) and installed 10.11.6. The installation went fine, however, I can't log in to the App Store app on the Virtual Machine because I get an error: "An unexpected error occurred while signing in. Your device or computer could not be verified. Contact support for assistance." I've tried restarting and logging in to the App Store several times, but the error persists. Any ideas what I should try next? /Applications/Parallels Desktop.app: CFBundleShortVersionString: 14.0.0 CFBundleVersion: 45124 UPDATE: I have also run all of the available updates in the App Store app (which can be done without logging in), and rebooted again, but still no luck signing in to see my purchases.