NTFS File and folder permissions are really important to Windows. Sometimes these permissions can be altered causing software or even the operating system to work in an undesired way.
The ICACLS command is designed to help you clean this mess up.
Launch the command prompt as an Administrator and navigate through the tree of folders you need to fix.
Then launch the command:
ICACLS * /T /Q /C /RESET
ICACLS will reset ntfs permissions of all the folders, files and subfolders. After a while, depending on the number of files, the permissions will be fixed.
Sometimes, you may need to take the ownership of a tree of folders before you can reset the ntfs permissions. You can use the command below before launching the ICACLS.
takeown /R /F *
Be careful, taking the ownership of system folders may break your operating systems.