Mac Says Startup Disk Is Full: How to Fix the Issue

When you see a warning message from your Mac saying that your startup disk is almost full, it's essential to take immediate action. A hard disk should never exceed 85% capacity, especially not your startup disk, as this can lead to slow performance and errors. In this article, we'll explore what causes this issue and provide steps on how to fix it.

What Is a Startup Disk?

Before we dive into the solution, let's define what a startup disk is. A startup disk is a disk on your Mac Catalina OS that has an operating system installed on it. In other words, it's the primary drive that loads when you turn on your Mac.

Finding Your Startup Disk

To find out which disk is almost full, we need to locate it. To do this, follow these steps:

1. Click on 'Finder' in the menu bar at the top of your screen.

2. Hover over the Dock at the bottom of your screen and open Finder.

3. In the window that opens, checkmark the 'Hard disks' checkbox.

Your desktop should now display the hard disks on your Mac as icons.

What's Causing the Issue?

To free up space on your startup disk, we need to identify what's taking up all the storage. We can do this by taking a closer look at our disk space. This will help us pinpoint which files or folders are occupying the most space.

Solutions to Fix an Almost Full Startup Disk

Now that we know what a startup disk is and how to find it, let's discuss some solutions to fix the issue:

1. Move Files to External Hard Drive or Cloud Storage: One option is to move files and folders to an external hard drive or cloud storage service like Google Drive or Dropbox.

2. Install a Second Internal Hard Drive: Another solution is to install a second internal hard drive on your Mac, which can provide additional storage space.

Clearing Up Space

To clear up space on your startup disk, we need to free up storage. This can be done by:

1. Deleting Unnecessary Files and Folders: Identify files and folders that are no longer needed and delete them.

2. Emptying the Trash: Make sure to empty the trash regularly to free up space.

By following these steps, you should be able to clear up space on your startup disk and avoid any potential issues with slow performance or errors. Remember, it's essential to keep your startup disk under 85% capacity to ensure optimal performance.

Mac says startup disk is full