Specs: MBP 15-in late 2011 running Yosemite 10.10.3


I have an external monitor that I've been using for about a year, but recently the Thunderbolt-to-HDMI adapter I have has been giving me problems (bad/fuzzy connection) so I bought a new one from amazonBasics. I used it for about a day with no issues, but while I was streaming a video, the monitor went gray and the audio started skipping. The keyboard and trackpad were frozen so I did a manual shutdown. When I tried to reboot, it would always get stuck at about 25% of the loading bar. I tried booting in safe mode, but pressing "Shift" at/before/during/after the chime didn't activate it. After pressing "alt" and choosing my secondary HDD and some dumb luck, I managed to finally boot my laptop. Everything worked perfectly. So I stupidly tried to troubleshoot the problem and found that both my old and new Thunderbolt-to-HDMI adapters cause this graphic glitch and break the reboot. However, if I run the laptop with no external monitor, it works fine (surfing and streaming). Then the battery died and I had the same issues trying to boot:

  • Sometimes there would be no progress bar (just a gray screen) and then the fans would speed up.
  • Sometimes the bar would get stuck at 25%.
  • And sometimes it would boot fully and have no problems afterwards.

I want to do a recovery from my Time Machine or reinstall OS X, but Recovery Mode doesn't work either.

TL;DR: I can't boot into Safe or Recovery Mode and I would like to recover from Time Machine or reinstall OS X.

Any ideas on how to permanently fix this booting issue?

  • Do you have a boot USB – Ruskes Jul 19 '15 at 3:46
  • I have one for Mavericks, but I'll make one for Yosemite. That will work differently than trying to boot from a Time Machine drive? – skamazin Jul 20 '15 at 15:44

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