DanMMM wrote:
Suddenly this morning, I try to access messages (text) and the machine repeatedly gives me an "internal error" message.. "restart".. Have done that multiple times with no success..
—SafeBoot How to use safe mode on your Mac - Apple Support
Takes a bit longer to get to the login screen, does a quick disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc.
Login and test. Reboot as normal and test. Caches get rebuilt automatically.