Why does Time Machine store local Time Machine snapshots?

DCarlson93 wrote:

I backup Time Machine to an external hard drive. How do I remove the local copies taking up space on my Mac?

I wouldn't if you value your user data— these local snaphot are the short term saves locally, whether you are connect to your TM are not, for easy access/recovery of your most recent files/edits/etc

If you ever accidental lost work or edits— it easy to revert to these stored backups.

ex

You can from the Terminal.app turn off this feature if you insist...

This will turn off local snapshots, copy and paste:

sudo tmutil disablelocal

About Time Machine local snapshots - Apple Support