MBP Mid 2014 randomly shutting down
For about 6 weeks (right after upgrading from Mojave to Catalina 10.15.5) my Mid 2014 MBP is shutting down more or less random. Note all of these shutdowns are not unexpected, i.e. there is no "Unexpected" dialog shown after power up.
It started as shutdown when going to sleep, right after the screen saver disappeared. I restored Mojave from TM, but the problem persisted.
After a clean Catalina install, the problem was still there, but less frequent.
I suspected a thermal problem, so got my MBP a cleaning job and new thermal paste.
After upgrading to BigSur, these shutdowns occur more frequently again, even while working. Intel Power Gadget shows no unusual load or temperatures.
I resetted PRAM and SMC more often than I can count.
Any hint to where I should look?
MacBook Pro 15″, macOS 11.0