One of our most customer requested features has been to allow the deletion of users whilst at the same time maintaining any historical transactions relating to that user.
It is now possible to delete (or archive) a user so that they are no longer able to login, don't appear in drop-down lists but at the same time will still be recorded in the audit log detailing any historical work they have completed.
If you delete a user that is currently being used in your account (for example related to a contract, part of a workflow, part of a collaboration) then its recommended that you replace this user with a current user - this can be done using the "Replace a Person" feature.
Before a user is deleted, you will be warned if they are still being used in your account - giving you the opportunity to replace them
For more detailed information about the new delete a user feature, please refer to the following article: Delete a Person Article