In this post, read the method to fix if Window 11 Download is Stuck. If the user upgrade to Window 11, but the download is stuck then to fix this issue you should restart BITS and Window Update Service.
www.office.com/myaccount - Windows 11 has been released. If your pc meets the simple Windows 11 system requirements, you can free upgrade your Windows 10 PC to Windows 11. Usually, if there are available Windows 11 updates, the update process may be automatically in the process. If not, you can go to Start > Settings > Update & Security > Windows Update to test for updates, and the Windows 11 update should start.
