So, today I was looking through a dashboard which contains the results of reports from our managed Macintosh computers, and I came across a lab computer with 86% of it’s drive filled.

Curious, I went in and started to investigate the issue.

On our lab computers we remove user home directories if they are unused after 3-4 days to help preserve drive space. The worst case scenario is that up to 20,000 students can sit behind one of our lab computers. Now that’s a lot of home directories and a loads of data.

Long story short, I came across a folder:  /private/var/folders which was over two hundred gigabytes in size.

Turns out this folder holds user cached files and other such temp files. A web search turned up this post with some very interesting and useful information:

http://blog.magnusviri.com/what-is-var-folders.html

So now we are in the process of implementing some changes to our home directory removal tool by adding some code which will also remove the cache/temp data of that user.

Hopefully this will help to reduce disk usage.

So if you find that your Macintosh computer’s hard drive is missing a lot of free space, hopefully this post will help you in figuring out what is using up some of the space.

A word of caution. Remove cached/temp files at your own risk. A worst case scenario can result in a system that won’t boot.

Test, test, test, test, test, test…