Most advices you will find on the Internet will suggest you to:
- check if Time Machine is enabled. If it is enabled – delete all backups and disable it.
- Reindex Spotlight
- Empty Trash
- Install and pay for some software to find useless files
In my case I tried almost everything except using paid software. I thought that the problem with large system folder appeared because I have updated Mac OS X from one version to another and there were some hidden system files which I can not access or view in System Information tool.
I almost gave up, and decided to reinstall Mac OS X, but before doing that, I decided to transfer all user profiles to another laptop. Using Migration Assistant on both laptops I started process of moving the data. At one of the last stages Migration Assistant started to evaluate size of every folder it can transfer. Under my user folder I saw “Libraries” folder with size over 40 Gb.
I opened Terminal app and changed folder to Library:
From there, I started to search largest files. In order to get folder size in human readable format in Terminal type the following:
du -hd1 .
du – is terminal command to evaluate storage space used by files.
-h – stands for human readable format (Kb, Mb, Gb rather than bytes)
d1 – stands for depth = 1
In my case the largest folder was /Library/Containers/com.docker.docker/Data/vms/0 and Docker.qcow2 file in it. I have uninstalled Docker long time ago and there were no containers on my computer, so I just deleted this file, and freed up about 25 Gb of storage. Actually there is a an article about this file at Docker FAQ page, in case you are interested.
I think there are many other similar files/folders which you can delete in order to free some space, but do it on your own risk. I don’t suggest you to delete anything if you don’t know what you are doing.