I currently have a 27″ Apple Thunderbolt Display that I alternate between my 13″ MacBook Pro as a second screen and my “headless” MacMini that I use as a home server.
I noticed the screen started to flicker recently which I put down to a loose Thunderbolt cable connection or potentially the Thunderbolt port becoming worn. However the display then failed altogether when I tried to wake up the Mac from sleep mode. This was a strange circumstance as I could hear the screen had power and it was able to play sounds. In addition the Display Preference panel in Settings showed it was connected.
I browsed the usual sites and discussion blogs for answers and none were conclusive in providing a straightforward solution. One of the more common solutions was to reset the PRAM and the SMC on the Mac and to date this seems to have solved my problem.
I have included a number of links below and source articles which may also be useful when troubleshooting this problem.
Please leave a comment below if you have found other solutions.
Despite my previous post, the screen failure returned! After multiple attempts with my own advice I eliminated that the fault was a software issue. I discovered that the combined power and thunderbolt cable from the Display was faulty.
I now have an instantly working Display by connecting my MacBook Pro via a separate Thunderbolt cable and a separate power cable.