Windows 10 build 18999 for insiders Early Access channel brought out a problem of Shutdown and Restart. Many users started complaining about the inability to turn off or restart the computer after they received the update. So Microsoft has released a patch KB4526447 to solve the issue on October 19, 2019.
KB4526447 includes the bug fixes for the shutdown and reboot problem. Additionally, the update will take the insider version Windows 10 20H1 to Build 19002.1002 (10.0.19002.1002) for Fast and Skip ahead ring.
KB4526447 will fix Shutdown and Restart Problem on Windows 10 [20H1]
You can manually download the update from following links –
1) x86.cab Google Drive
2) x64.cab GoogleDrive
3) ARM – Windows10-KB4526447-arm64.cab GoogleDrive
After downloading, rename the file properly and then install it.