Thunderbolt USB not working in Yosemite

have there been any solutions suggested? this is very annoying... like going back in time..

This worked for me, too.

what I did.

I turned off bluetooth while everything was hooked up.

Unplugged MBP15 2014 from the one thunderbolt connection (2 total TB monitors) and power

shutdown MBP

Turned on MBP

after computer was started up i plugged in power and TB connection

USB keyboard and facetime camera now work

Turned on bluetooth

everything is back to normal.

This all started when a client came in and i brought my computer to the conference room to drive the presentation on AppleTV, upon reconnecting to my normal setup no USB worked nor did TB facetime cameras

please let us know how you go...

I have a Mac Book Pro 13-inch, Early 2011 and i use Thunderbolt to connect to my Sony TV.

Since the recent Yosomite update i can't get the display to appear on my TV. the Display on the computer adjusts its size and the preferane say it is using my TV however the TV remains blank 😟

Never had a single problem before...

and i stuck because i use this TV setup for doing work...

I have the same problem - have you been able to fix this? I have tried everything. I own a Macbook Pro 13" Mid 2012. Yosemite has been working well until my recent upgrade to version 10.10.3. - what a mistake!! Eventually gave up, formatted drive, reinstalled everything & my Thunderbolt Port still doesn't work. Terribly frustrating. When I try to upgrade ThunderboltDisplay firmware I get an error - "No Thunderbolt Displays were found". uuuuugh...

I have exactly the same problem. 😕

Me too. 2011 Thunderbolt display, into Mac Mini Server.

Frequent black screens since around the time Yosemite arrived. Also usually no light grey screen on booting up, then about one in every five, it re-appears. Doesn't seem to be heat sensitive as sometimes it's cut out in the first few minutes, from cold. Other times it behaves for hours, then blacks out. The only thing that brings it back is a force quit - reboot.

Seems my only hope is a bug fix or product recall if enough people make enough noise.

Followed your steps as written and it resolved the non-working TBD USB ports. Thank you for sharing and saving a lot of hassle.

Yep! This worked for me too. Thank you so much gregb22.

So just to give you a bit of extra info here, this seems to def be a Yosemite issue. My TB display is normally plugged into my MacPro running Mavericks. Never been a problem. My MacBook Pro was running Mavericks until yesterday and I often plugged the TB display into my MacBook instead to use the bigger screen. Agaian, never been a problem.

yesterday i upgraded my MacBook Pro to Yosemtie. Today I plugged my TBD into it and it worked fine UNTIL i then plugged it back into my MacPro. It was then that the USB ports stopped working.

Following Greg's advice i turned off bluetooth, unplugged the TBD, rebooted, then plugged it into a different TB port, USBs and FaceTime now working again. Bluetooth back on, everything working fine.

Needless to say I WON'T be plugging in my MacBook Pro into this screen again until this issue is resolved. It's such a shame that these bugs can remain for so long without anyone fixing them. Surely pretty simple??