Generally speaking, your startup disk is the primary storage device for holding your operating system and all your files. One day while using your MacBook, you are presented with a warning: “ Your startup disk is almost full.” Additionally, you should empty your Downloads folder frequently and delete old Time Machine Snapshots.Īn all too common situation many Mac users find themselves in is the startup disk running out of space.Deleting them is simple, or you can use a 3rd-party program like CleanMyMac X. System Cache folders can take up space.Unwanted programs and apps can consume valuable space, too, so you can clear up space by removing them. The Trash can take up a lot of space, so you should make sure to empty it often.If you have a lot of pictures, videos, and documents, you can save space by moving those to an external backup or iCloud.You should check your Startup Disk to determine what is taking up space. Over time, your Startup Disk may fill up with unnecessary junk and files. The Startup Disk is where your operating systems and files are stored.Restart the Mac, then Check Storage Again.Method 1: Move Your Personal Files to iCloud.