Why does my MBP say it was restarted "because of a problem"?

Solution 1:

I had the same annoying issue on OSX Mavericks (10.9.2), and resetting the NVRAM / PRAM as per Andrew Ferrier's answer didn't resolve it.

Instead, I opened a Terminal window and found a week old Kernel .panic file in /Library/Logs/DiagnosticReports/

I simply renamed it to .panic.old with the following command:

sudo mv Kernel_[rest_of_filename].panic Kernel_[rest_of_filename].panic.old

After a reboot I no longer get the annoying message!

Solution 2:

Resetting my NVRAM / PRAM appears to have resolved the problem.

Solution 3:

I had a similar problem with Big Sur. NVRAM/PRAM reset didn't work, but resetting the SMC apparently did:

https://support.apple.com/en-euro/HT201295