rMBP External Monitor Prevents Boot

[TheBeverage]

Hi all,

Recently (possibly since 10.9.3 or 10.9.4) I've been having an issue with my rMBP where, if I turn it on with an external monitor attached (via mini displayport, for the record), it makes the Apple chime, starts loading, then the screen goes black and it starts over with the message about having to restart due to an error. Then it will loop a few times before giving up and shutting off entirely.

My "solution" so far has been to boot with the monitor unplugged, then plug it back in after... except that doesn't always work either. About 50% of the time, only in the last week or so, doing that causes the external monitor to not have to work at all. I have to reset my computer a couple of times every time I turn it on lately, which is really becoming a pain.

Any help would be appreciated. I've tried resetting the SMC to no avail, though I'm not positive I did it right. I held shift, control, and option and the power button then released them simultaneously, but the MagSafe light did not flicker or change states, which I was told indicates it worked. I'm not sure if that always happens, though.

 

[DeltaMac]

Boot to your hardware test. (Restart, holding the D key)
http://support.apple.com/kb/HT1509
(for the Hardware test, run both standard and extended tests)

if you have a Mac released after mid-2013, you may be able to run Diagnostics, instead of the hardware test.
http://support.apple.com/kb/HT5781

If that test passes, then try a different video adapter/cable.

 

[Weaselboy]

...though I'm not positive I did it right. I held shift, control, and option and the power button then released them simultaneously, but the MagSafe light did not flicker or change states, which I was told indicates it worked. I'm not sure if that always happens, though.

This is one of the things an SMC reset can fix. Did you hold shift-control-option on the left side of the KB? Right side won't do it.

 

[DeltaMac]

This is one of the things an SMC reset can fix. Did you hold shift-command-option on the left side of the KB? Right side won't do it.

I guess a mis-type?
SMC reset is left side Shift-Control-Option, and press the power button, all at the same time.

 

[Weaselboy]

I guess a mis-type?
SMC reset is left side Shift-Control-Option, and press the power button, all at the same time.

Yes... exactly. Thanks

 

[TheBeverage]

Yeah, it was all on the left side. I'll try the diagnostic hardware scan when I get home, see if that fixes it. Could it really be a cable issue though? I've never heard of a bad cable preventing booting.