With the recent rollout of the Windows 10 May 2019 Update (1903), customers started reporting This PC can’t be upgraded to Windows 10 error messages during the Windows 10 upgrade process.
What needs your attention
The following things need your attention to continue the installation and keep your Windows settings, personal files, and apps.
This PC can’t be upgraded to Windows 10.
Your PC had hardware that isn’t ready for this version of Windows 10. No action is needed. Windows Update will offer this version of Windows 10 automatically once the issue has been resolved.
According to Microsoft, these error messages might appear on machines with the USB drive, memory card or other external storage devices connected. Because of the external drive connected, the setup might result in inappropriate drive reassignment during the installation process.
In order to resolve this issue, prior to the upgrade, please remove all external storage devices and reboot your machine. After the reboot, you should be able to run the setup without this error message.
You might also receive this error message when trying to perform a clean installation of Windows 10 May 2019 (1903) from a DVD or USB thumb drive. To fix this you should copy installation files from an external drive to local drive or partition and then start the installation again.