Salesforce archives certain events and tasks every Saturday at approximately 5:00 AM Greenwich Mean Time (GMT). You can view archived activities in certain locations in Salesforce.

Activities Archived by Salesforce:
1. Events due more than 365 days ago

2. Closed tasks due more than 365 days ago

3. Closed tasks created more than 365 days ago, if they have no due date

To View Archived Activities:
1. In weekly data export files

2. By clicking View All in the Activity History related list

3. In the printable view of the Name or Related To record

4. By using the URL for the activity, if you know it

5. Archived activities aren’t included in activity list views or reports.

Additional Considerations for Activity Archiving
1. Sandboxes
When you create or refresh a sandbox, archived activities aren’t copied.

2. Deletion
Archived activities can be deleted manually, but Salesforce doesn’t automatically delete them.