When you configure encryption for a sensitivity label and a user applies it to a file with assigned permissions, the access control is enforced by Microsoft Purview Information Protection (formerly AIP). If the owner of the file leaves the organization, access to the file depends on how permissions were configured:
What happens when the owner leaves:
The file remains protected by the label's encryption settings. If permissions were granted to specific users or groups, those users continue to have access. If only the departing user had full permissions, and no additional access was granted, others may not be able to access the file.
Recommendations:
"If the user who protected the content is no longer with your organization and no other user has rights to the content, you must use the super user feature to access the content." Source – Microsoft Learn: Rights Management super users
Microsoft recommends using the Rights Management super user feature, which allows designated administrators to access all protected content, even if the original owner is no longer available.
Best Practices:
Assign access to groups instead of individuals whenever possible. Ensure the Rights Management super user role is configured for recovery and compliance scenarios.
For more details refer: Source – Microsoft Learn: Rights Management super users
Sensitivity label encryption for Australian Government compliance with PSPF
Restrict access to content by using sensitivity labels to apply encryption
I hope this information helps.
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