Open Finder > Applications > Utilities > Disk Utility Solution 1: format hard drive under macOS 10.13 High Sierra with Disk Utility Now, let's start to format a hard drive under macOS 10.13 High Sierra with some easy tools. First of all, get your data backed up before do the format. In this article, we will introduce you a few tools you can use for formatting hard drive under macOS 10.13 High Sierra. When you have the need to format a hard drive under macOS 10.13 High Sierra, it typically requires the use of third-party hard drive format software like Disk Utility.