So you need to make a big NTFS rights change. Well before changing anything do you have a good backup of the old permissions? Most people will say I got a backup. But restoring the backup will take much longer than restoring just the permissions.

So how do I make a backup of the NTFS permissions?

icacls c:\windows\ /save AclFile /T /C /Q

So lets break this command up

icacls = command to run
C:\windows\ = directory/file to run the command on
/save = command to excute
AclFile = where to save the ACLs
/T  = Recurse the directory
/C  = Continue even after a single failure
/Q = Dont print information about successful files.

What if we need to restore now then?

icacls c:\windows\ /restore AclFile /T /C /Q

So lets break this command up

/restore = command to excute

Problems?

Well a standard problem is that you saved the acls using icacls E:\Shares /save.... and are trying to restore using icacls F:\Shares /restore.... The ACL file does contain the path in the command. So in that case I would suggest changing the directory in the command Prompt so you could run the command as icacls . instead.