is it safe to grant permission to all users in Microsoft sql server
I'm not entirely sure what problem you're trying to solve, but if you grant the kind of access you're describing to &quot;Everyone&quot; and you get hacked, now you have opened up a lot more possibilities for someone to do damage to your systems. That is access that they could not have done if access had only been granted to a select few people.  It sounds like you want to have certain people with the ability to move database files around as needed. This will require a login and user and the ALTER DATABASE permission as well as an AD group that is either a local admin on the server or has been granted specific access to the folder(s) where the database files are stored. See the below question and answer about ALTER Database.
https://stackoverflow.com/questions/9798968/permissions-required-to-run-alter-database-set-single-user-statement-on-sql-se