It depends whether you’re going to boot macOS from it, on the space required for snapshots, and how large they could become. And there’s more.
free space
Why Time Machine makes snapshots, and how they can grow and apparently consume free space. What you can and should do to manage this.
One likely cause of vanishing free space are large snapshots. So how can you tell why a snapshot is large, and how can you avoid it?
Snapshots are of great value, but can grow large if you don’t keep an eye on them. If you find Time Machine or another backup utility is storing large snapshots, here’s what to do.
Confused by this on APFS? So you should be, as it’s complicated by features like snapshots, sparse files, and the file system itself. There’s no single figure.
Have you checked how much free space is on your startup volume after the last update? Do you wonder where it has all gone?
How to store a 400 GB sparse bundle on a volume which only has 200 GB free space – provided that you don’t actually use the space that isn’t there.
The volume should only be half full, but installers and other software complains there’s insufficient free space. What to do.
New version tells you free space available on your backup volumes, as well as checking for errors occurring during backups.
Should you defragment files, or free space, in El Capitan, or are they even possible now?
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