You can't just keep putting data on a drive forever, whether it's your primary hard drive, the little flash drive in your pocket, or the big external hard drive on your desk.

Even a demonstrably gigantic 16TB hard drive has a limit: 16TB! As crazy as it sounds, even that can fill up. Granted, it takes two million high-quality photos to do that, but "only" about 150 4K movies.

It only takes a minute or two to check how much storage space you have on your drives. It's especially easy to do if you're using File Explorer.

In Windows 11 or Windows 10, select the Start button, followed by File Explorer (the small folder icon). If you don't see it, look under the All Apps or Windows System folder, or type file explorer into the search box.