I have unintentionally removed everyone’s permission for one of the partition on my hard disk. It’s on Windows 7. Anyone would be in panic when all of sudden you lost control to 10Gb of data.
However after going through some readings, I found the solution was quite simple. No it was not ‘system restore’.
The answer: restart in safe mode, right click on the drive, properties, click security tab, then some users like administrator, pc users, authenticated users, and system to the permissible list.