After 10.6.8 Mini Displayport to HDMI PROBLEM

Thanks for the links. I just filed a bug report. Apple needs to fix this seriously. As of now I can't use the iMac in 10.6.8 and I'm afraid I'll have to avoid Lion until this issue is fix.

Same issue here. (MacBook Pro 17" + 2009 iMac 27" i7 2.8GHz). Makes it nearly impossible to use this setup at night!

Not sure which update it was, but one of the minor updates in the recent round of updates fixed it. Run Software Update and see if that doesn't take care of the problem.

hmmm weird. Both MacBook and iMac are running the latest point release (10.6.8).

Was there a display-related update?

It was some minor update released after the 10.6.8 release. Like I said, I just ran Software Update a few days ago and it fixed it, so I'm not sure which update it was. It probably had some obscure name with an obscure description.

That sounds great!!! Thing is I'm really scared to try it because if it doesn't work for me then I have to go back and reinstall the OS again or restore from TM backup. If there are a couple more people here with the same success story you have I'll give it a try. Not saying I want others to be the guinea pig for me, (I guess I am, sorry) but I can't be that adventurous as this iMac is for TV and for work purposes. 🙂

Amit Gupta I believe it was a second thunderbolt update that superkev07 is talking about. It showed up for me July 17th when scanning for new software. It's weird because in my Installed software list it now shows up as Thundbolt firmware update v 1.0 . I already had the same version installed July 15, but for some reason they applied it again.

Unfortunately the second thunderbolt update didn't help my mbp (early 2011 w/ thunderbolt) connected to my iMac (2010 without thunderbolt).

I have now installed Lion on the iMac, still can't adjust the brighness when connected to the mbp. Little hope that a Lion install on the mbp will help but will give it a shot now.

Same problem here with my late 2009 27" i7 iMac. Whether connecting my 360, PS3 or MacBook Pro 2010 model to my iMac, I cannot adjust the brightness anymore after going to 10.6.8 from 10.6.7, and Lion didn't fix it.

Really, really bummed about this. 😟

Any savvy users out there who can figure out what files changed from 10.6.7 to 10.6.8/Lion that would disable the brightness adjustments?

I hope I'm wrong, I sincerely hope I'm wrong but I think Apple may not repair this issue. It's really odd that also continues to be in Lion. That makes me think they changed something that required disabling the brightness control. I'm bummed because my iMac is my livingroom TV and I can't turn down the brightness when connected via mini displayport to my Comcast cable box anymore. As mentioned earlier I'm still on 10.6.7, can't do a software update to 10.6.8 and Lion is out of the question for my iMac if they refuse to restore this function.

I'm wondering if any people with a 2011 iMac with the thunderbolt port are experiencing this in Snow Leopard or Lion?

Judging from the messages in this thread, this issue affects both Thunderbolt and Mini DisplayPort equipped iMacs. This bug was introduced into Lion and Snow Leopard at the same time, so hopefully it can be fixed!

I really think the best way to get this resolved is for some clever person to figure out what file/s changed from 10.6.7 to 10.6.8 and Lion, and manually replace them ourselves. I just don't know where these files may be, but I'm not as programmer-y inclined as other users...

Please, clever person/people out there: help us!

I can add that the new re-release of the 10.6.8 update released by Apple today, July 25, did not fix the issue, either. 😟

OH NO!!! This is truly bad news. I wonder if Apple intentionally did this for some other reasons. I can't upgrade my iMac to Lion now. Both 10.6.8 and Lion have disabled the brightness controls. Even worse it defatults to maximum settings. I'm really upset at this point.

Apple should fix this (everyone please submit a bug report), but in the meantime I suggest you all use Shades. It is free software and solved the problem perfectly for me. http://www.charcoaldesign.co.uk/shades