When you use the SCANREG /RESTORE command at a command prompt in MS-DOS mode to restore the registry, you may receive an error message stating that the registry was not restored.
This behavior can occur if a third-party program (such as Norton Unerase) has the drive's disk access locked.
To work around this behavior:
Restart the computer. Press and hold down the CTRL key until the Startup menu appears.
Choose Step-by-Step Confirmation, and load only Himem.sys. Press N for all other prompts.
Run the SCANREG /RESTORE command.
This behavior is by design.
Himem.sys is not required to run Scanreg.exe, but is required for Scandisk.exe and other tools that may be needed.
It may not be safe to unlock the drive.
The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.