So, for example, if your MacBook has 128GB of internal storage, 300GB of backup space is generous. Generally, you want to use 150% or more of your Mac’s internal drive capacity. (If you don’t know how, check out this post, which also gives you some other handy Mac skills, including how to run Terminal, which you’ll need to use in this post.)Īfter that, find out the amount of storage you need for the backups. Determine the OS version and suitable backup limitīefore you can fix Time Machine’s storage, you first need to determine what version of macOS you’re running. Creating a separate partition on your backup drive is the best way to control the amount of storage Time Machine will use.