Sometimes we’re asked if Techtool Pro works with SSDs. Short answer? Yes!
For a longer answer, some of Techtool Pro’s features don’t really apply to Solid State media. Some of the confusion probably comes from whether it is a good idea to optimize (or defragment) a Solid State Drive (SSD). Techtool Pro does display a warning when attempting to optimize an SSD, because doing so is not recommended.
Defragmentation routines organize the data on rotational hard drive platters so that the data can be read consecutively, without the drive having to move the drive mechanism any more than necessary, which improves read times on rotational disks. SSDs have no mechanical moving parts, and fragmented data can be read just as fast, regardless of the physical location of the data on disk. Furthermore, moving massive amounts of data on an SSD (which occurs during any defragmentation operation) works against SSD-specific features used to keep them running their fastest.
On SSDs formatted Mac OS Extended, you can still optimize, despite the warning. On drives formatted APFS, optimization is not available, and it is doubtful that Apple will provide the necessary tools to make an optimization available for APFS formatted volumes. This is likely due to some of the same reasons listed above, that defragmentation isn’t really something that is needed with Solid State media, and there aren’t many Macs left equipped with rotational media.
Aside from the Volume Optimization tool and the Volume Rebuild tool, which can still perform many repairs on APFS formatted disks, every other test and tool for disks in Techtool Pro works exactly as it would on a rotational drive. And there are, of course, even more tests and tools in Techtool Pro that work on components in your Mac besides disks.
Pro Tip: Be sure to perform all of the drive tests on your SSD to make sure it is running at its best.