My Macbook Pro TBar started dying. Heating up. Loads long. When restarting it goes to critical update but error comes up in the process. Using High Sierra.

Please post the EtreCheck output as a "Reply" to this thread

<https://discussions.apple.com/docs/DOC-6174> or <https://etrecheck.com>

Use the EtreCheck "Share" button to "Copy Report" (See the image below)

And then Paste in a "Reply" to this thread.

If, AND ONLY IF, you get the error:

"The message contains invalid characters"

then try posting to PasteBin.com, and give us a PasteBin URL link.

<http://pastebin.com/>

.

EtreCheck is a tool that helps Apple Support Community volunteers debug problems without any access to the troubled computers. Debugging problems can be a difficult task even when the machine is in front of you. Attempting it via a discussion forum is extremely difficult. EtreCheck is a great help that regards.

You should also try an SMC reset and an NVRAM reset

<Reset the System Management Controller (SMC) on your Mac - Apple Support>

<How to reset NVRAM on your Mac - Apple Support>

If you are still under warranty and/or have AppleCare, call them. Let them deal w/it.

OOW: Take your Mac to your local Apple Store or an AASP. Diagnostic testing is FREE!

goes to critical update

I know of no Mac software that produces such a message.

What is that error message, exactly?