Installation Assistant or Upgrade Assistant stuck at 99%

If the progress of Windows 11 Installation Assistant or Windows 10 Upgrade Assistant is stuck at 99% for more than four hours, here’s something you can try.

Resolution

Option 1

Make sure you follow these steps before you restart your PC. Otherwise, the Media folder might be unavailable.

1. Open File Explorer, type C:\$GetCurrent, and then press Enter.
2. Copy and paste the Media folder to the desktop. If you don’t see the folder, select View and make sure the check box next to Hidden items is selected.
3. Restart your PC, open File Explorer, type C:\$GetCurrent in the address bar, and then press Enter.
4. Copy and paste the Media folder from the desktop to C:\$GetCurrent.
5. Open the Media folder and double-click Setup.
6. Follow the instructions to start the upgrade. On the Get important updates screen, select “Not right now” or “Not at the moment”, and then select Next.
7. Follow the instructions to finish installing Windows 10/11.
8. After you’re done, make sure to install available updates. Select the Start button, and then select Settings > Update & Security > Windows Update > Check for updates.

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Option 2

Use the Windows 10/11 ISO or USB setup disk to install Windows.

1. Download the Windows 10/11 ISO.
2. Double-click the downloaded ISO to mount it to a drive-letter.
3. Run Setup.exe from the mounted ISO drive-letter.
4. In the initial screen, click “Change how Setup downloads updates”
5. Select “Not right now” or “Not at the moment”, and click Next.

   

6. Follow the instructions to finish installing Windows 10/11.
7. After you’re done, make sure to install available updates. Select the Start button, and then select Settings > Update & Security > Windows Update > Check for updates.

(Also, see Windows 10/11 Upgrade Stuck at Checking for Updates and Windows 11 Installation Assistant Error 0xc00000f0)