Step four: Rip it up and start again

Erasing a whole drive is possible, but you’ll need a backup

When you feel like your Mac is hopelessly cluttered, it might seem easier to delete everything and start from scratch than work out what to remove. If all your work, photos and other content was in iCloud, you could theoretically just erase your Macintosh HD, reinstall macOS, then let everything sync back. In reality, it’s never that neat, and you’ll need to ensure you don’t lose data.

One approach would be to manually copy all of your own content to an external drive, erase your startup drive and reinstall macOS (as in step 1 of ‘How to restore files after reinstalling macOS’, opposite), then copy everything back. Time Machine (see p24) can make this more foolproof.

Same again

In System Preferences > Time Machine, check that you have a complete up-todate backup stored on your external drive. Click Options to check that you haven’t excluded anything from the backup. Then follow one of the processes shown opposite, either to restore the whole backup or to reinstall macOS and then selectively restore content.

Restoring everything isn’t logically going to save any room, so the most likely time to resort to this is if your drive is not just full, but behaving oddly – perhaps losing space for no reason, or refusing to free up space even after emptying the Trash. Try Disk Utility to check and repair the drive before resorting to this.

Belt and braces

We really can’t emphasise too much: unless you have a good reason to take drastic action, don’t. If you do go for a reinstall, remember that once you erase your drive, the only copy of your crucial files, until you restore them, is your backup – which is the same as not having a backup.

If your work is synced to iCloud Drive, that’ll serve as an extra backstop (and don’t worry, although the act of manually deleting a synced file would delete it from iCloud Drive too, erasing your whole drive leaves your iCloud Drive intact, ready to sync back). If not, try to make a separate copy of anything important elsewhere.