In the first part of this series, I went over some of the very simple things that you can do to tune up your Mac. One of the objectives mentioned there was to always keep at least 20% of the boot disk free. In this installment, I will go over some of the easy things you can do to free up space on your boot drive.
The first thing to be done when making any changes is BACKUP YOUR BOOT DISK. Before you start making any substantial changes, it is always a good idea to update your backup.
I would also suggest checking to see how much free space you have before you clean up your boot drive (in the ‘Finder’ >> File >> click on ‘Get Info’). Jot the amount of free space down so that you can compare it with what you have when you have finished to see just how much the effort has benefitted you.
Easy Disk Cleanup
While having a full boot drive may not be the biggest contribution to having a slow computer, it can cause other weird side effects on daily use . OS X, as most modern Operating Systems, uses a lot of Virtual Memory. If there is not sufficient free space on the boot disk for Virtual Memory, system performance will be degraded [2, 3]. In addition, most applications use various types of temporary files while they are running. If there is not enough disk space for these files, the application may crash or fail to start .
Therefore, periodically reviewing what is taking up space on the boot disk is of significant importance. If it has been some time since the boot disk has been examined, there may well be several gigabytes (GB) of unnecessary files taking up space. Regardless of how large the boot drive is, you should review it to see what can be eliminated, particularly if there is less than 20% of free space remaining. As you review the files and folders, you will need to sort them into one of three categories: keep, remove and move to a Storage Drive .
Empty the Trash – This seems like it should be obvious, but one of the routine tasks each of us must perform is to periodically empty the trash . As we discard files, they generally are sent to the Trash. These files will remain there until you take steps to permanently delete them. To do this click on Finder >> Empty Trash. This will permanently remove what ever is in the Trash and free up the space. If you have not emptied the trash in a while, this can easily add up to significant disk space. If there are multiple users for your Mac, each user will need to empty their own trash.
NOTE: Once files have been emptied from the Trash, they are not recoverable! If you have any doubt about needing a file, move it to your Storage Drive instead of the Trash.
Storage Drive – You may find that there are files that you still want to keep, but because of their size or low frequency of use you do not what them to remain on your boot drive. In some cases, a second drive can be installed into your Mac and made into a data drive. Generally though, you will want to get an external drive that attaches by Firewire (IEEE 1394), USB or Lightning cable to your Mac. Which of these connection technologies you can use will depend upon your specific Mac. A quick look at Mac vendor OWC shows that external drives start from $75 and go up depending on the type and size of the drive. I found an external 120GB USB drive on Amazon for just over $31. By shopping around you may well find lower price models available. I will talk more about adding drives in a later issue of this series.
Clean the Downloads Folder – We are all constantly downloading files [4, 5]. Generally, these files will be placed in the Downloads folder. Open Finder >> select your Home directory >> Downloads. Select to see the contents in list form, then click on the Size column heading to see the content sorted by size. This will easily point out which files you will free up the most space by deleting or moving to your Storage Drive.
iTunes Files – Video files are very large, so a few of these that you no longer need can take up substantial space. If you have bought TV or movies through iTunes, you may have both HD and non-HD versions. Space can be saved by deleting the one you do not intend to use . Open a Finder window >> Your Home directory >> Music >> iTunes >> iTunes Music >> Movies. Now drag to the Trash those you do not want or move to the Storage Drive those you want to save.
If you have been backing up (ALWAYS advisable) your iOS devices to your computer, you may have old, unused iOS Apps taking up space . In your iTunes folder, you’ll notice the folder “Mobile Applications”. This is where backups of your iOS Apps are stored. Even if you have deleted the App from your iOS device, the backup will still be present. It is a good idea to review the contents of the directory to see if any of these files can be removed. Open a Finder window >> Your Home directory >> Music >> iTunes >> Mobile Applications.
iMovie Files – If you have been using iMovie, you should review these files. Open a Finder window >> Your Home directory >> Movies. Check here and in all of the sub-directories for any files that can be deleted or moved to the Storage Drive.
iPhoto Files – If you take a lot of pictures, you may well have some in your iPhoto library that are simply not good enough to keep. It is a good idea to periodically review your photos and simply delete (select the photos, then hit the DELETE key) those you no longer want. I deleted 1061 pictures from my iPhoto library and that recovered 5.24GB of disk space.
The iPhoto app is a little odd in that when you trash a photo it does not go to the OS X Trash. Instead it goes into a separate local Trash within the app. As a result, if you do not empty the Trash within the App, pictures that you have discarded are not really deleted. I found that substantial space can be tied up in the iPhoto Trash.
To address this, open iPhoto >> then click on Trash in the left column >> click on Empty Trash in the upper right corner. This will finally erase and free up the space from the photos that you have deleted within iPhoto.
Search for Large Files – The Finder allows you to search for large files. Rather than to manually look for files you can delete, use the Finder to see what will give you the most return. Open a Finder window >> File > Find (or hit Command-F). On the Search line select “This Mac”, then click on the “Kind” drop down and choose “Other”. When the “Select a search attribute” window opens, check the box for File Size, uncheck any other boxes, and click OK. Change the “equals” pull-down menu option to “is greater than” and then change KB to MB. Enter a minimum file size such as, say, 100MB or even 10MB. After the search completes you can see the larger files on your system and delete any you no longer need — or move them to the Storage Drive. 
Remove Apple Supplied Files – OS X includes many files that you may not necessarily need. Loading hundreds or even thousands of Font files can impact system performance . You can save some more space by removing fonts that you do not use . You can do this by opening the Finder >> Go >> Go to Folder >> entering “/Library/Fonts”. Fonts that you do not use can then be moved to the Trash to delete them, or to your Storage Drive. Most of these files are fairly small (less than 20MB) so little space is going to be saved. Unless you have a relatively small hard drive I am not sure that removing these files is very beneficial. The entire Fonts directory is less than 1GB, but if you have a small boot disk this might help.
Similarly, you can check the following folders for files you might be able to do without. I have noted the approximate space in each taken up on my Mac Mini. Unless you are in dire need of saving space these are probably something that you can overlook.
/Library/Desktop Pictures (< 450MB)
/Library/Modem Scripts ( < 1.5 MB)
/Library/Printers (< 300 MB)
/Library/Screen Savers/Default Collections (< 150MB)
/Library/Widgets ( < 60MB)
Now that you have removed some files, it is time to Empty the Trash again. Check again how much free space you have on your boot disk (In the ‘Finder’ >> File >> click on ‘Get Info’). How much more free space do you have now?
There are more ways of reducing the space being used on your boot drive, but those will have to wait until Part 3 of this series.
1 – How to Give Your Mac a Performance Boost
2 – Mac Performance Tips – Keep Plenty of Free Disk Space
3 – 11 No Cost Tips for Optimizing Mac OS X 10.4 Tiger Performance
4 – What To Do When Your Mac’s Startup Disk is Almost Full
5 – Liberation: 10 OS X steps to free Mac disk space
6 – How to clean and speed up Mac OS X Mavericks
7 – Tuning Mac OS X Performance
8 – SPEED UP MAC OS X LEOPARD
See all of my Mac OS X related posts