We spend a lot of time talking about drives. And indeed, Techtool Pro includes a number of tests and tools for them. However, perhaps the next most important component when it comes to your data is your Mac’s memory (RAM).

Your RAM is temporary storage used to store whatever your Mac is currently working on. Since the operating system can hold on to memory used by other processes that have recently been closed, the Memory Test in Techtool Pro reclaims as much memory as possible before testing. Any memory currently in use by the operating system or reserved by a running application is unavailable for testing. To test the most RAM possible, it is best to quit any running applications. Even better, start up from an eDrive or Protogo device, which have slightly smaller operating system footprints.

And what if you find a memory test failure? If your Mac has removable RAM, you might try removing one memory module at a time (while the computer is off, and immediately after touching something metal to avoid static damage), restarting the computer, and then testing again to see if the problem persists. If not, you have likely found the culprit and can replace it. If your Mac has RAM that cannot be removed, your only recourse is to take your Mac to an Apple Store or an authorized Apple repair center.