It seems that this is a common issue that many users have faced while trying to upgrade to Windows 11. There are a few possible causes and solutions for this problem, depending on your situation.
One possible cause is that your PC does not meet the minimum system requirements for Windows 11, such as having a compatible processor, enough memory and storage space, a secure boot and TPM 2.0 enabled, and a supported graphics card and display. You can check the system requirements for Windows 11 here. If your PC does not meet the requirements, you may not be able to install Windows 11 using the installation assistant.
Another possible cause is that there is a bug or glitch in the installation assistant that prevents it from completing the installation process. This could be due to a corrupted or incomplete download, a network or power interruption, or a conflict with other software or hardware on your PC. You can try to fix this by doing the following steps:
1.Restart your PC and try to run the installation assistant again. Sometimes, a simple reboot can resolve the issue and resume the installation.
2.Delete the temporary files and folders created by the installation assistant. You can find them in the C:$WINDOWS.~BT folder and the C:\Windows\SoftwareDistribution\Download folder. Make sure you delete all the files and folders in these locations before running the installation assistant again.
3.Run the Windows Update Troubleshooter to detect and fix any problems with Windows Update that might affect the installation of Windows 11. You can find the troubleshooter in Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update.
4.Disable or uninstall any antivirus, firewall, or VPN software that might interfere with the installation of Windows 11. You can also disconnect any external devices or peripherals that are not essential for the installation, such as USB drives, printers, scanners, etc.
5.Use an alternative method to install Windows 11, such as using an ISO file or a media creation tool. You can download the ISO file or the media creation tool from here. You can then use them to create a bootable USB drive or DVD and install Windows 11 from there.