I have a late 2011 13″ MacBook Pro with OS X Mavericks updated to the latest version, which was usually connected to a HP Pavillon 23xi monitor using a Mini DisplayPort to VGA adapter. It worked like a charm as desktop extension until 3 days ago. When I woke up the MacBook it didn't detect the external display.
I connected the screen to another laptop using the same VGA cable and it worked. So the screen and the cable are fine. I ran a live cd of Xubuntu on my Mac, and recognizes the screen perfectly, so the adapter and the Mini DisplayPort works properly.
However when starting with OS X, sometimes it doesn't detect the external screen, sometimes it detects it, and extends it, but the external screen is black. I can move the mouse to the second desktop, but logically I can not see what is in it. It worked perfectly well until 3 days ago. I Googled for a solution, and I tried the following with no luck:
- Resetted the PRAM with alt + cmd + p + r until I heard the startup dong 3 times
- Resetted the SMC with ctrl + alt + left shift for a few seconds and releasing all keys at the same time.
- Reinstalled OS X Mavericks.
- Restored a Time Machine backup of a month ago (when the screen worked properly).
- Repaired 2 times the permissions of the disk.
- Verified that I had the latest EFI and SMC firmware.
I've done all this and still have the same problem. (I think I need to reset something, but I don't know what else I should do.)