Mac OS X Clean up: Disk Space Retrieval Guide

What to do if your Mac has no more space to store important files? Having enough storage on digital devices has become more important than ever before. Modern affordable MacBooks are mostly equipped with a 256GB onboard SSD. As a result, they may face an issue of the insufficient amount of storage space. Sooner or later, users face the need to configure their data to deal with the “Your startup disk is almost full” warning alert.

How to Fix Mac OS X “Startup Disk Full” Issue?

Users often get puzzled when their Mac says “Your startup disk is almost full” or gets stuck on the white screen during startup. The warning message looks menacing, so less experienced Mac users start googling what it could mean and how to fix their device. Some users believe their Mac has suffered a virus attack. However, this is not a rare case with Apple computers. Users running an OS X Yosemite server have reported a similar issue with a standard 256GB SSD configuration.

message "statup disk almost full"

What is a startup disk on a Mac OS X?

os x startup disk full

Mac’s startup disk is a separate partition on your Mac’s SSD which contains the operating system. Other partitions store applications and user data. It is crucial to keep at least 15% of the startup disk space free to ensure smooth Mac OS performance. If the amount of data on your startup disk exceeds the 85% limit, your Mac will suffer system errors, freeze-ups, and performance loss. Depending on the Mac OS version installed on a Mac, the cleaning methods may slightly vary. However, there are three proven ways to deal with ‘startup disk full’ issue:

Manual cleanup

Inbuilt MacOS utilities

Third-party cleaning applications

Startup Disk Cleanup on Mac OS X El Capitan

Users of Mac OS X El Capitan can do a manual startup disk cleanup. Please note, this is a multi-stage procedure, which can take significant time.

1 Go to Finder -> select All My Files in the left sidebar. Alternatively, use the Command-Shift-F (⌘+⇧+F) shortcut to display the files. To make necessary file sorting and arrangement, click View in the top bar -> select Show View Options. To display the biggest files first, select Size. To sort out the outdated files, choose Date Last Opened. Feel free to choose the preferable file arrangement to see all possible cleanup options.


sort user files

2. In the left sidebar, select Downloads and press down Command-I shortcut to see the available space. Locate the unneeded files and move them to Trash.

3. Empty the Trash if it doesn’t contain important data. If there is doubt, take a peek into the Trash folder and restore the needed files. To purge Trash for good, use a Command-Shift-Option-Delete key combination. Alternatively, you can right-click the Trash icon and select Empty Trash from the drop-down menu.

activity monitor

4. OS X El Capitan requires plenty of RAM to function properly. Check the Activity Monitor to control the RAM usage and remove the memory-demanding applications. Go to Finder -> Applications -> Utilities -> Activity Monitor or look it up in the Spotlight, then click the Memory tab. Quit the RAM-consuming processes manually, or launch Terminal and execute the sudo purge command

5. Cashe files are the scourge of earlier Mac OS X versions, including El Capitan, as they need regular cleaning. Go to ~/Library/Caches/ Remove only the contents of the cache folders, but don’t delete the folders. Repeat the same actions for /Library/Caches (omit the “~”) and ~/Library/Logs.Cache files are located in multiple folders, so it might take plenty of time to clean them up. When finished, reboot your Mac. Note: The system-level applications generate temporary files and caches, most of which shouldn’t be removed.

Library Logs

Startup Disk Cleanup on Mac OS X Yosemite

Storage tab

Users of OS X Yosemite and earlier face a situation when the Other folder takes up the significant part of their Mac’s storage. Other is a tricky folder containing multiple types of files, disk images, system and user caches, fonts, app plugins, extensions, etc. The files stored in different folders belong to the Other section. Typically, Mac users don’t concern themselves with looking into it until all the free space is gone.

mac os x startup disk

It is impossible to get rid of the Other folder. However, users can reduce the overall space occupied by it:

this mac
  • To locate and delete large documents from Other, press Command-F from the desktop -> select search This Mac -> choose Other from the sorting drop-down menu. After that, select the File Size and File Extension options to sort the documents.
  • To remove large archives, enter DMG/ZIP in the Finder search field -> Search This Mac -> sort the results by Size.
  • It’s worth checking all installed web browsers for unused add-ons. FYI, Google Chrome is not recommended for using on OS X Yosemite due to its significant consumption of system resources.
  • Although iTunes backups of iPhone and iPad data are not directly related to Other, these files can occupy plenty of disk space. To delete temporary files and system files, go to /Users/User/Library/Application Support/. For instance, if you made any iPhone or iPad backups, most likely you’ll find them in ~/Library/Application Support/MobileSync/Backup.

Startup Disk Cleanup on macOS Sierra and High Sierra

macOS Sierra and High Sierra provide users with the inbuilt Optimized Storage toolkit. To access Optimized Storage, click on the Apple icon -> choose About this Mac -> click on the Storage tab -> Details.

Store in iCloud helps you reclaim startup disk space by transferring rarely used files into the cloud storage. Click the Store in iCloud button and select the offered options to start the file transfer.  In case you wish to tweak the settings of iCloud Drive or disable it completely, go to the Apple menu -> System Preferences -> iCloud.

Optimize Storage can help you remove watched films and TV shows from your startup disk. Also, it is possible to make settings for downloading only recent email attachments. Click the Optimize button-> tick both preference options in the pop-up -> confirm by clicking Optimize.


It is possible to tweak the iTunes preferences to save up startup disk space:

  1. Click Optimize -> select iTunes.
  2. Go to Preferences -> select Advanced.
  3. Put a tick next to ‘Automatically delete watched movies and TV shows.’

To set up the email attachments download in Mail:

  1. Go to Mail -> Preferences -> Accounts.
  2. Choose an email account to configure the settings.
  3. In the Attachments pop-up menu, select Recent or None.

Reduce Clutter can help you find big and old files to purge them from your Mac’s startup disk. Use Reduce Clutter to scan the contents of Applications, Documents, and other folders. Click Review Files to sort out Large Files, Downloads, and access the File Browser. This way, you will be able to see the largest files, preview and delete them afterward.

Using Third-Party Apps for Mac OS X Startup Disk Clean Up

Third-party software can be helpful to recover startup disk space. Apart from versatile cleaning features, out-of-the-box applications contain an array of tools for Mac OS X maintenance and optimization. In particular cases, third-party programs run a background system scan. For instance, cleaner has a Smart Assistant that monitors Mac OS X in the background and alerts users of possible problems. Resorting to third-party software is an option when manual cleaning and onboard utilities failed. Applications provided by third-party developers have a user-friendly interface and troubleshoot issues effectively.

In Conclusion

There are three ways to fix “Your Mac Startup Disk Is Almost Full” problem and reclaim startup disk space on a Mac. It is possible to do the manual cleaning, use onboard Mac utilities or third-party apps. Depending on the Mac OS X version running on a Mac, users should pay attention to specific aspects of cleaning. Each of the above methods works well; however, third-party applications prove to be the most effective.