After installing Windows 10, I got the message, " * Critical Error * Start Menu and Cortana aren't working.
We'll try to fix it the next time you sign in. " As directed, I logged out and back in, shut off and restarted
several times, but nothing worked. Web search showed you could revert to the previous version of Windows,
but the critical error message wouldn’t let me use anything. Even installed programs compatible with Win10
like Adobe InDesign wasn’t working properly.
1. In the critical error message, click to log out.
2. Don’t log in. At the bottom right, click the power symbol, then click Restart and hold down the Shift key.
Keep holding Shift down while the computer goes down and restarts. This should take you to a Windows menu page with a number of options. The last option will allow you to revert to your previous version of Windows.
3. If your computer comes back to the login window, repeat hold down Shift and Restart. I had to do it 3 times
before it gave me the menu.
open CMD Try A System File Scan
type command - Sfc /scannow
and try Another method
open Cmd
chkdsk c:/f
restart the system