Chosen Solution
Hello, My MacBook Pro freezes completely during or right after the login screen. First I was thinking that only my Keyboard and Trackpad wasn’t working, but when I was looking for the time after a while and I saw that it was incorrect so the screen is also completely frozen. If I’m fast enough sometimes I can run a task after login in, but it freezes directly about 10-20 seconds after start up. In Safe Mode everything works perfect and smooth like you would normally expect. Only the graphics are slower and no sound allowed what is normal in Safe Mode, But no issues or flashing screen. Apple Diagnostics are also perfect, zero hardware issues shown. The strange part is when I plug an HDMI cable in before starting the Mac with HDMI connected bypasses the freezing issue! The Retina display and External TV works together without problems, everything is responsive keyboard trackpad screen , just like normally. But the second that you remove the HDMI cable from the Mac it freezes directly and you need to force shut down the Mac. Already formatted the whole SSD inside, installed High Sierra, Mojave Clean install, but nothing changes. Even tried to start Sierra on External SSD with USB and works until the Login and freezes like the internal SSD. Maybe malware, virus? Please Help and thanks in advance ! Aldo B.
OK, I’ve seen this before! The way this system sends the video output is a bit convoluted if you look at the schematics. The signal is muxed between the DisplayPort (DP) output and the HDMI output. The DP signal is then muxed still again between the internal display and the Thunderbolt port to service a DP or Thunderbolt connected display. The chip U9750 is where this takes place. I would check around it for corrosion, or a damaged or missing resistor or cap as they are needed sink the signal so the switch is clean between the two external loads. The chip in on the back side of the logic board, here is a BoardView of the spot
The cheap solution is to just use a HDMI plug to offer up the load. Or you can see if the logic board is repairable.
Seems like you have tried nearly everything. It appears to be either a Logic Board problem or a Hard Drive or SSD problem. Let’s try a new SSD first and them move onto replacing the Logic Board. [linked product missing or disabled: IF123-123-1] MacBook Pro 13" Retina Display Mid 2014 SSD Replacement https://www.powerbookmedic.com/MacBook-P… MacBook Pro 13" Retina Display Mid 2014 Logic Board Replacement
