Macbook keeps rebooting randomly

Uninstall Trusteer by following the developer's instructions. Anti-virus apps, cleaning/optimizer apps, and third party security software is not needed on a Mac. These types of apps usually cause more problems than they solve, plus they impact system performance.

macOS already provides great built-in security especially when the user also practices safe computing habits as outlined in this excellent article by a respected forum contributor:

https://discussions.apple.com/docs/DOC-8841

Hi revred,

Thanks for posting in Apple Support Communities.

We understand that your Mac is restarting and no hardware problems were found in Apple Diagnostics. To address this behavior, start by making sure you have all available software update installed for best performances. If you notice this issue only when using a specific app, update the app or remove it. If the issue continue after you reinstall the affected app, it would be best to contact the software developer for more information.

*Use safe mode to try to isolate the cause of the issue.

*Reinstall macOS. If the issue continues after reinstalling macOS, check your hardware.

Check your hardware

Learn how to check your connected devices and other hardware.

Check peripheral devices first

If you don't have any devices attached to your Mac, skip to the next section.

1. Shut down your Mac.

2. Disconnect all peripheral devices, such as hard drives or printers. If you have a desktop Mac, make sure that only a display, keyboard, and mouse or trackpad are connected.

3. Turn on your Mac.

4. Use your Mac for the amount of time that it would usually take for an unexpected restart to occur.

5. If an unexpected restart occurs, follow the steps to check the internal RAM and third-party hardware.

6. If an unexpected restart doesn't occur, turn off the Mac and connect one peripheral device at a time until an unexpected restart occurs.

Check RAM and third-party hardware

Certain models of Mac computers have removable memory (RAM). If you recently installed memory or a hard disk (or SSD), make sure that it's compatible and installed correctly. If possible, remove it and test with the original memory or disk.

Find these steps in If your Mac restarted because of a problem.

Regards.

revred,

Thanks for letting us know.

Please do not hesitate to reach back out to us if you have questions or need any additional support. Thanks for using the Apple Support Communities. Cheers!