What is Icacls?
Icacls is the replacement for cacls (Change Access Control Lists), a command-line utility that allows you to show and perform some operations on ACL for files or directories.
ACL (Access Control List) is a list of permissions for a filesystem object and defines how its security is controlled by managing who and how it can be accessed.
Actually, operations on ACL are not the only ones possible with this tool.
What makes it a powerful tool is also the ability to perform backup and restore operations on ACL for files or directories, or to search for files that have a specific user as owner.
And in addition, in the event that an ACL is damaged or destroyed, with icacls you can restore it by resetting it and setting default permissions or inheriting those of the parent.
icacls e:\*.* /reset /t