Retention and versions
Each successful backup creates another recoverable state. Retention controls how much history remains without allowing old copies to consume the entire destination.
The newest copy answers “what do I have now?” Earlier versions answer different questions: “What did this look like yesterday?”, “What was in the folder before I reorganized it?”, and “Can I recover a file that disappeared last week?” A backup with only the newest state cannot answer those questions.
Managed thinning​
The standard policy keeps dense history while changes are fresh and thins it as they age:
- Every version from the most recent hour
- One version per hour for the last 24 hours
- One version per day for the last month
- One version per week for older months
When the destination runs low on space, the oldest eligible backups can be removed automatically. The newest stored version of every protected file is kept.
This graduated policy preserves detail where it is most useful. Recent mistakes are often noticed quickly, so recent versions remain dense. Older recovery points are spaced farther apart, providing long-term history without treating every hour from months ago as equally valuable.
Optional limits​
Depending on the selected policy, you can keep all versions, limit retention by age, or let available destination space set the practical boundary. More history improves recovery choices but requires more capacity.
Keep all is appropriate only when destination growth is monitored and storage is intentionally expanded. A time limit is predictable but can remove the only old copy of a rarely noticed deletion. Space-managed retention adapts to actual usage but still requires enough room for current data.
What counts as a version​
A new copy is needed when the source file changes. Unchanged data is not rewritten unnecessarily. Deleted source files remain recoverable while a retained restore point still references them.
Retention is not immediate synchronization: deleting a source file from a backup pair does not necessarily remove all historical copies. Use the restore timeline to select the state you need.
Example​
Suppose Budget.xlsx is edited at 09:00, 10:00, and 15:00. The backup may initially retain all three versions. As they age, the policy can thin the dense history while keeping representative hourly, daily, and weekly points. Restoring from noon shows the 10:00 version; restoring from the previous day shows the version that existed then.
Retention operates on stored history, not on the live source. Removing an old restore point does not delete the current source file.
The first backup size is only the baseline. Frequently edited media projects or databases can produce much more history than mostly static documents. Review destination capacity after the first week.