HD file size reporting discrepancy

David Tomer wrote:

[I saw similar questions here, but >5 years old, so posting new.]

Really? This is probably one of the most commonly reported problems.

My 500G Mac Mini HD free space shows different on:

Disk Utility - 25G free

About this Mac / Storage - 325G free

About this Mac /  System Report / Hardware / Storage - 25G free

Finder / Show Status Bar - 325G free

325G free should be correct.

25G free is correct.

Also, if you carefully review all of the above values, you'll notice that they actually don't say that at all. They use the word "available", not "free". People think those two words are the same, but they are different.

I first noticed this when SuperDuper told me my HD had 475G used, which I knew couldn’t be right and would result in not enough space for the backup.  I discovered I had accidentally recorded a “movie” using Launchpad/Screenshot and it recorded a huge file, about 250G.  Before I found and deleted, Time Machine had backed up, ran out of space, and I understand likely stored that file and others on my HD.  I deleted that file and 325G free is typical.  After doing that, I got the above values.

The cause is probably a local snapshot. Deleted files will be saved in a local snapshot for about a day or so. Only after the snapshot is purged will the 250G file be truly deleted and that storage moved into "free" status.

However, since you are using a 3rd party backup tool, your system could be behaving differently.

Do not use SuperDuper but use the Other Cloning Software

Whether the below applies to SuperDuper - you will need to explore this with the Developer of Shirt Pocket Super Duper

Notation - If the user is using a cloning software like Carbon Copy Cloner - suggest tweaking the Safety Net Feature in this software. It may be making additional Snap Shots that are not being Cloned to the Eternal Drive. If this should be the case, these Snap Shot could be using additional space on the drive

Automated maintenance of the CCC SafetyNet folder