To function efficiently the system needs free space to remain on the hard drive, and the more, the better. After some time the disk fills up with data and Mac begins to send alerts. Obviously, you need to clear up your disk to get rid of them. Ignoring it may cause serious problems: open documents may be lost, tabs in browsers may not be saved, and account settings may disappear, etc. Regaining about 10GB will be enough. In most cases, it helps, but sometimes, the problem lies elsewhere and is not related to the lack of space.
It is necessary to look through files you have on your hard drive and divide them into three categories. There will be the ones you need but can store somewhere else, the ones that are just dead weight and can be removed and the ones that should be left on the disk to let the system work smoothly.
It may be that you can make do just by deleting something, without transferring files to other media, or vice versa. To determine your next steps:
- Open the Apple menu and choose About This Mac.
- Go to the Storage tab to see what takes up the disk space.
It may be that the Backups section is too big. The thing is a built-in tool called Time Machine, stores local backups by default. To stop it from doing this and remove backups you do not need, use Terminal. Press Command+Space key combination and type Terminal to open it. Then enter sudo tmutil disablelocal and check if you have enough free space after rebooting your computer.
Delete Unnecessary Files
You can also use Finder to detect space eaters.
- Open any folder in Finder, and then press Command+F key combination to for the Finder Search feature to show up.
- Choose This Mac in search parameters, and File Size as the primary search operator.
- Then you can set up the file size you are looking for with a is greater than search operator.
- Look through the list and decide which of them you do not need anymore. Remove only the ones that cannot affect the system for sure.
Move Your Data to the Cloud or External Devices
Your data from the first category can be transferred to the external media or the cloud. You do not have to spend much money to buy additional space, as many cloud storage services like iCloud, Dropbox, SugarSync, CertainSafe, etc. offer a certain amount of gigabytes for free. For instance, pCloud gives you 10GB just for creating an account.
Empty the Trash
It is possible that you just forgot to empty the Trash and all the deleted files continue to take the disk space.
Use Disk Utility
If you continue getting messages about your startup disk being almost full, there may be a problem with a corrupted hard drive. Especially if you see that the System section is way too big in the Storage summary. Try running First Aid Disk Utility:
- Click on the Spotlight icon and type Disk Utility or access the program via Finder in the Applications
- Open it and choose the First Aid tab.
- Run the First Aid tool, and then restart your Mac.
This usually helps if other options do not work.