Internal keyboard and trackpad not working
I am currently using a Macbook Pro 13”retina 2015.
I usually use my Mac in bootcamp for work purposes (Windows). I connect my MacBook to an external HDMI monitor and use a USB mouse & keyboard.
It worked fine, until after awhile, I turned on my Mac to then use the built-in keyboard and trackpad both were not working. The only key working was the power key. I could not enter recovery mode or use any start up command keys since the keyboard was unresponsive. It only worked with my USB (Logitech) external keyboard and mouse.
The trackpad was not detected in system preferences. The weird thing is it still force shutdown when I enter combination: shift+control+option+power button (so the keyboard is kinda working). In some cases, when trying to log on, a bluetooth device search tab appears.
I went to the Apple Store to get it serviced. The technician reinstalled my OS and formatted the drive. The built-in keyboard and mouse worked! And after using my external keyboard and mouse, everything stopped working again. He did not really know the cause of this problem.
I'm pretty sure this isn't a hardware issue as stated above, the shift+control+option+power button still works. I think there may be some error or setting problems.
Note: I have never dropped fluid onto my laptop or dropped it
Would really appreciate any help to resolve this issue. Thanks