Does Tower’s Safe Upgrade option actually create a pre‑upgrade snapshot of the Preferences file?

The Short Answer

No. The "Safe Upgrade" option in Tower does not create a discrete, timestamped snapshot or backup of the Preferences.plist file. It is designed to ensure the application bundle is replaced without corrupting the installation, but it does not provide a file-level rollback mechanism for user configuration.

Likely Behavior vs. Confirmed Facts

In the macOS ecosystem, application updates typically separate the Application Bundle (the software) from the User Preferences (the data). Tower follows this standard pattern.

• Confirmed: The Preferences.plist is stored in ~/Library/Preferences/, which is outside the application bundle. A standard upgrade replaces the .app file but does not touch the preferences directory.
• Likely Explanation: The "Safe Upgrade" toggle likely refers to the integrity of the binary replacement process—ensuring the old version is fully removed and the new version is correctly registered—rather than a data backup utility.
• Uncertainty: Because the installer does not explicitly document a snapshot step, any assumption that a hidden backup exists is unsupported. If the Preferences.plist becomes corrupted during a version migration (e.g., due to a schema change), the installer cannot automatically restore it.

Manual Verification Steps

If you wish to verify whether a backup was created on your specific version, follow these steps:

1. Open Finder and press Cmd+Shift+G.
2. Navigate to ~/Library/Preferences/.
3. Search for any files starting with com.symmetricub.Tower that have a timestamp or .bak extension.
4. Check the macOS system log by running the following command in Terminal to see if the installer performed any copy operations:

   log show --predicate 'process == "installer"' --last 1h

Recommendation

Since there is no native rollback for preferences, you should manually duplicate your Preferences.plist to a secure location before performing an upgrade if you have complex custom Git credential helpers or specific environment configurations.

Diagnostic Detail Needed: To provide a more precise answer, please specify the exact version of Tower and the macOS version you are using, as installer behaviors can vary between legacy versions and recent releases.