Mastering Office 365 Administration

Disabling user login

Experienced admins know that it's almost always a mistake to delete a user immediately. Deletion triggers an assortment of consequences, some of which can't be reversed easily—or at all.

Instead, the immediate responsible action to take is to disable the user's ability to sign in. If you have concerns that someone may accidentally unlock the account, you can optionally change the password as well for an added layer of protection.

Later, you can perform other activities like those described in this section to ensure the user's mail and files are preserved after their departure. Once you've gone through your company's data preservation process, you may safely remove the user's licenses and delete the Office 365 account. ...