If you check which version of Windows 10 you're currently running and it's not version 2004, it means Windows doesn't consider your PC eligible for the update.
Fix All Windows Update Error Issues in Windows 11/10 (2023)
What's the problem? According to ZDNet, the update, also known as the Windows 10 May 2020 Update, is blocking PCs from upgrading due to incompatible drivers and certain PC settings. PCs running Windows 10 version 1809, 1903, and 1909 are said to be affected.
Confirming the issue: Microsoft watcher Paul Thurrott also ran into this issue when trying to update from version 1809, saying on Twitter that he's "never seen this before." Another user on Reddit experienced the same issue when trying to upgrade from Home to Pro.
"This PC can't be upgraded to Windows 10. Your PC settings aren't yet supported on this version of Windows 10. Microsoft is working to support your settings soon. No action is needed. Windows Update will automatically offer this version of Windows 10 when these settings are supported," reads the message they received.
