Timeshift restore left home-directory changes in place after a system snapshot rollback

The Default Behavior: Protecting User Data

p>By design, Timeshift is built as a system recovery tool, not a backup solution. The intended default is to exclude the /home directory to ensure that a system rollback only reverts the operating system (packages, configurations, and system files) without deleting or reverting your personal documents, photos, or browser data.

Answering Your Trade-offs

• Is excluding home the intended default?
  Yes. By excluding /home, Timeshift ensures that a failed update or a system rollback doesn't result in the loss of work created since the snapshot was taken. It creates a clear boundary between the OS state and user-data state.
• Is there a way to restore only the system portion if home is included?
  No. If you include /home in a snapshot, Timeshift treats the entire snapshot as a single unit for that specific snapshot mapping. There is no documented toggle within the GUI to perform a "system-only" restore from a snapshot that explicitly includes the home directory.
• Does the answer differ between RSYNC and BTRFS?
  The core logic remains the same, but the mechanism differs. In RSYNC mode, Timeshift copies files; exclusion is handled via file filters. In BTRFS mode, it uses subvolume snapshots. While BTRFS technically allows for more granular snapshots (snapshotting just the @ subvolume), Timeshift's implementation does not expose this granularity to maintain simplicity and prevent data corruption.

Recommended Strategy for Predictable Rollbacks

To achieve the predictable behavior you need without losing personal data, consider the following architectural approach:

1. Keep Home Excluded in Timeshift: Continue using snapshots without /home. Use a separate backup tool (like Deja Dup, TimesBorg Backup, or rsync) for your personal data. This separates "system recovery" from "data protection.".
2. Use Application-Level Configs: If you need to revert app settings that live in home, move those specific configurations to /etc (if the app supports it) or use symlinks to system-wide directories that Timeshift *does back up.
3. Manual Snapshotting for Risky Changes: If you must include /home in Timeshift, you must manually back up /home before performing a rollback, then manually restore those files after the system revert is complete.

Verification Command

To verify your current configuration, run the following command to see which directories are currently included/excluded:

timeshift --list-filters