What is the ‘Other’ data hogging all the disc space on my macbook?

I have a friend who  has a 120 GB MacBook Air and his hard drive was filling up. There were lots of suggestions on the Internet as to what might be causing it – Spotify cache,  system files, movies,  but what’s the best way to find out what is using up your hard disk space?  An old but I think still the best application for doing this is Disk Inventory X.  I wrote an article back in 2010 on how to use it here: Disk Inventory X.   Seven years later disc inventory X is still the best app for this so here’s a bit of a reminder on how to use it.

If you go to your Apple menu and then select “About This Mac” and then select the “Storage”  tab you will see a graph like  the one above. This shows you your hard drive and each colour represents different parts of the hard drive and what documents are on it. As you can see most of my hard drive is full of documents and photos and there are some system files.  Some people are reporting a block of data called ‘Other’  which can be 30 GB or more!   How can you know what  is using up the space?

Enter Disc Inventory X.

You can download it from here.

When you run Disc Inventory X you will be given a screen like the following one which will show all the hard drives on your computer. Click on the hard drive that you want to examine and then select “Open Volume”.

After you do this Disc Inventory X  will analyse your hard drive, this can take 5 or 10 minutes, it’s okay to leave it running in the background and go and do other things on your computer in the meantime. Once it is finished it will give you some folders on the left and a diagram on the right like this picture below.  The diagram on the right shows you your hard drive. You can click on any of the boxes on the right and in the left-hand side window you will get the name of what that file is.

For example, in the screenshot below I have clicked on the big blue box in the top left, and the menu on the left tells me that this is my “Photos” library.

Alternatively, you can click on folders in the left window and how much space those folders take up will be highlighted in the right window.

I suggest you spend  5 or 10 minutes looking over your hard drive and learning what takes up the most space.  You can keep a record of the files that you may want to delete.  In my friend’s case he had multiple old iPhone backups that were over a year old and took up 30 GB!