> Disk and system maintenance tools
Disk utilities, and other apps including some anti-malware checkers and cleaning apps, are designed to manage data at a low level and are a potential minefield when you upgrade.
After you upgrade to High Sierra, don’t even think about trying to use your older version of tools such as DiskWarrior, Carbon Copy Cloner, SuperDuper, and the like without first checking the website of the publisher to find a version that’s explicitly designed to work with your new version of macOS. Don’t say we didn’t warn you.
This applies to any macOS update, but particularly to High Sierra due to extensive underlying changes. It also applies even if your Mac has a hard drive rather than an SSD that’s been converted to the new file system, APFS. Trying to use older versions of maintenance utilities such as TechTool Pro, Drive Genius and App Cleaner will not only be unreliable but could corrupt your data.
Technical changes that are normally invisible may cause a lot of stress if you use outdated maintenance tools.