Overview:
The Status field (generally Active or Inactive) cannot be edited when clicking on the Edit button on the record.
Root Cause:
The record's status is governed by an Object Lifecycle.
Solution:
Create an Object Lifecycle Workflow to control the Status. Or, disassociate the Object Lifecycle from the Record Type. (Note: Disassociation can only be processed if all records are deleted)
Related Documentation:
Vault Help Documentation: Configuring Object Lifecycles