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Reasons your SSD may be slowing

If your previously snappy Mac is feeling sluggish, the reason could be the SSD. If you use the Disk Speed tool, and find that the write speeds are drastically slower than they should be, run the Volume Structures and Surface Scan tests first. If neither finds problems, and particularly if you're using an after-market SSD, there are two reasons that could be.



Solid State Drives utilize a cache to make the majority of small writes as fast as possible. Caches on most drives are relatively small, however, so if you see a drop off in write performance, it is likely because the cache is full, and the disk is now writing directly to the disk.

Read more: Reasons your SSD may be slowing

Drive Speed tool in Techtool Pro 13

There are numerous variables which can contribute to the responsiveness of your Mac. In particular, if your Mac has an SSD, and if TRIM hasn't been able to keep up with clearing disk space, your speedy Solid State Drive can start to feel like an old rotational hard drive. It might not be immediately obvious, however, without measuring the performance of your SSD. Techtool Pro 13 introduces a new tool to do exactly this.

Disk Speed Catalina

Read more: Drive Speed tool in Techtool Pro 13

Mac Troubleshooting with a T2 chip

If disaster ever strikes, and you find you cannot start up your T2 equipped Mac, it helps if you have made a few preparations. The T2 chip that is built into modern Macs provides a number of important features, including security features. By default, this security is very tight, similar to using iOS on an iPhone. This prevents starting up from any external drive or anything other than the current signed OS available from Apple.

cancel mac

Techtool Pro users need more freedom than this security provides, and fortunately, a quick trip to macOS Recovery provides this freedom. After starting up in macOS Recovery, launch the Startup Security Utility, and use it to reduce your Mac's security. More details are available here.

Read more: Mac Troubleshooting with a T2 chip

Using Snapshot Recovery in Techtool Pro 13

Your SSD utilizes TRIM to erase sectors in order to keep write performance snappy. Because of this, traditional data recovery has been nearly impossible for these drives. With APFS, Apple introduced APFS Snapshots, which preserve the state of a drive at a specific point in time. Until recently, these were used to bridge the time between Time Machine backups. In Techtool Pro 13, the Techtool Protection preference pane can create Techtool Pro snapshots. These snapshots can be set to last much longer than Time Machine snapshots, making the snapshots a much more useful data recovery option.

Snapshot Sunset

To get started, first make sure that Techtool Protection is installed. If it isn't already, the option to install it can be found in the Techtool Pro application menu. In Techtool Protection, choose the Snapshot Usage feature, and select any APFS volume that you wish to create snapshots for. Additionally, you can specify how long snapshots will last, and how often they are created.

Read more: Using Snapshot Recovery in Techtool Pro 13

What to do when Surface Scan finds bad blocks


Whether you have a Solid State or Rotational Drive, Techtool Pro's Surface Scan test may discover bad blocks at some point. A bad block, or bad sector, is a portion of the disk that can no longer be written to. Both types of devices utilize a cache of spare blocks that are used when bad blocks are found in order to ensure that your data does not get corrupted by storing it on a bad block. When the Surface Scan test finds bad blocks, this means that this cache is no longer able to use spare blocks, and your data will be at risk of corruption.

Surface Scan Catalina

In almost all cases, discovering bad blocks means that the drive will need to be replaced. Bad blocks represent physical problems with a disk, and cannot be repaired in software. In rare cases, a rotational drive can get a small lease on life by performing a secure erase on the disk. For rotational drives, this can cause the cache to reset, and may provide a few additional spare blocks. This generally does not work on solid state drives, however.

Read more: What to do when Surface Scan finds bad blocks

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