You might see an error message explaining this when macOS fails to empty the Trash. You can't delete these backups because they contain copies of your system files, which SIP protects. Apple introduced it in OS X El Capitan in response to a growing number of malware threats directed at macOS. This is a security feature in macOS that stops you or anyone else from damaging important parts of the operating system. Most of the time, you can't delete Time Machine backups from the Trash because of macOS's System Integrity Protection (SIP). Why Time Machine Backups Get Stuck in the Trash It's a nightmare scenario, but there are a couple of ways to remedy it. You'll find you can't empty the Trash, you can't put them back where they came from, and doing so hasn't freed up any more space on your external drive. When you move Time Machine backups to the Trash, they often get stuck there.
You might think it makes sense to drag them to the Trash-like everything else on your Mac-but that's actually the 'the wrong way.' If you tried it, you probably found out why it's a problem. It turns out there's a right way and a wrong way to delete Time Machine backups on macOS.
