> I can’t copy my Time Machine backup
i’m trying to move my time machine backups from their current 2tb external drive to a new 4tb model. about halfway through, macos reports a “–41 error” and aborts. what’s wrong? Before going any further, check that you didn’t install any utility software for this new drive. If you did, uninstall it before trying again. Although sometimes useful, these tools aren’t necessary and can cause compatibility issues at times like this.
Once you’ve done that, you need to reformat the new drive using Disk Utility, ensuring that it’s set to Mac OS Extended (Journaled) format. Time Machine backups can still only be made to a drive in that format, not the newer APFS kind. Next, in Finder, press Shift+Cmd+C, select the drive and choose File > Get Info. In the permissions section, ensure “Ignore ownership on this volume” isn’t ticked.
Turn off Time Machine and drag the folder Backups.backupdb from your old drive to the top level of the new one. You’ll then have to authenticate using your admin username and password, and give the copy operation plenty of time to complete. Unfortunately, you can’t copy a Time Machine backup using a third– party tool like Carbon Copy Cloner.
If that doesn’t work, go to Time Machine’s pane in System Prefs and turn on its menu bar icon. Hold Alt, click that menu bar icon and choose Verify Backups. Follow the on– screen steps to check for and perform any necessary repairs. You can try First Aid in Disk Utility too, although that invariably takes a long time, and can throw up its own errors.