My computer keeps just restarting randomly after updating to Sonoma

Hello brettj1976,

Thank you for using Apple Support Communities. If your Mac is restarting on its own, we'd like to recommend some steps to help troubleshoot this issue. First, we recommend that you review this resource on steps you can try: If your Mac restarted because of a problem - Apple Support

Check your software

* Install all available software updates.

* If your Mac suspects that a particular app caused the restart, it might ask whether you would like to move the app to the Trash. Click Move to Trash, then contact the software developer to see if a software update is available.

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

* Reinstall macOS. 

Check your hardware

Shut down your Mac, then disconnect all peripheral devices (such as hard drives or printers) from your Mac. If you have a desktop Mac, make sure that only a display, keyboard, and mouse or trackpad remain connected.

Then turn on your Mac and use it for the amount of time that it would usually take for an unexpected restart to occur.

If disconnecting devices resolves the issue, isolate the issue to a specific device: Connect one device at a time, testing again after each connection, until the issue returns.

If disconnecting devices doesn't resolve the issue, use Apple Diagnostics to test your Mac while your devices are disconnected.

We hope these steps help you. Thank you for using Apple Support Communities. Take care.