Why does my entire system freeze when I watch YouTube after Lion install?

I'm having this problem with VLC 1.1.11 on a 2010 mini. I tried a clean install of Lion and got the same result. It always seems to happen in full screen mode. The audio keeps going while the image freezes. A hard reboot is the only way out.

Youtube and flash have not been involved.

I to have had the problem of video cause my iMac 21.5" i7 Quadcore to freeze up. I have noticed it 4 times with YouTube and 1 time with Quicktime. I have taken the advice and have checked that iTunes open in 32 Bit.

I ran the Lion GM for about a week before the retail version was released. I had none of these problems. The only big change is the Java update and the iTunes update. I susspect they may be the cause.

My call to apple led to clearing my Chache files and doing a PRAM reset. This did not work as I had a lock up of the system about 15 min.

I will keep you posted if the iTunes method does the trick.

Forgive me if already mentioned, try installing Perian version 1.2.3 (latest version as of 30 July 2011).

I am able to play YouTube videos within Lion at the moment, however the only reason playback occassionally stops for me is because I'm using substatndard mobile USB internet at the moment (Voda..... in Spain) and they appear to be throttling/inhibiting the internet bandwith and connection dropouts, yet if I use cable ASDL at a friends round the corner then all is well.

Adding my name to the list of people having this issue. It's happened to me at least 5 times. I have a 27" iMac 2011, OS X Lion. It's not just YouTube, it's any flash video. I have the same symptoms others are reporting -- all applications are frozen, and I can only move the mouse. I can't restart, I have to hold the power button and do a hard restart.

This never happened under Snow Leopard. Hope there's an update to address this issue ASAP, as it's a near daily occurance for me.

Same problem here, Lion freezes on my iMac (2011) everytime I watch videos, especially after restarting from sleep. Browsing the web, it seems many users are having trouble with this same issue. Will Apple release a patch soon? I'm thinking of uninstalling Lion and going back to SL unless they come up with a solution soon. It's sad to see that Apple has become yet another Microsoft. Even Windows 7 never gave me such problems after a system update!

I can tell you launching iTunes in 32-Bit mode is not the answer. The freezing happens each time my computer come back from sleep mode. Side note to all of this is my computer will not wake upon network access. Not sure what the work around to all this is, but for now I am assume video related activity after waking from sleep mode will be a no go. I may be downgrading back to Snow Leopard, which is as big of a hassle as dealling with this problem.

I am attempting my second call to AppleCare. This is unacceptable.

I have a 21.5" iMac i7 Quadcore that is 3 months old. I am running OS 10.7 and this locking up of my machine has litterally put me at my wits end. AppleCare wants to run typical troubleshooting I have already done on my own.

I haven't had a bit of trouble with a previous Snow Leopard intall or with the OS 10.7 GM. This is something that came about after upgrading several different applications after upgrading to Lion. Apple can pretend this is not an issue all they want, but this clearly is a large enough issue.

I beleive this may be related to the recall on the hard drive recall.

I dont think its related to the HD recall. Its been happening to my 27" imac i7 w/ SSD and a 2 TB hitachi (not part of the recall). I called applecare a few days ago. Strange that it didnt seem to be happening in my admin or a new test account i had made for the call. Cleard out everything in Safari and seems to have helped. though im not very confident about that "fix" (under reset Safari "clear all website data" havent really had time to test a lot since though.

Well it was just a thought. Spoke with a Case Specialist. Ran disc permmisons and disc repair. Started in Safe mode and created a test account. Can't recreate at the moment. I will try clearing out Safari, but Freeze happens in Quick Time as well so I am thinking that may not be the solution.

Having the same issue with freezing, Just received my new 21.5in 2.8Ghz 4Gb ram (running Lion) imac i7 2-3 days ago and has already frozen on me 5+ times and had to hard reboot each time. Everything freezes except the mouse. 1st time freeze the apple sign top left still worked so could force quit the item causing the freeze... cant recall which program that was now... but after that has been a full freeze and all from Youtube. Downloaded the Java/install enabling the prgram and could watch a few You tube videos. Even after putting it to sleep for 2hrs. Then after having it up and running for a couple of hours just using the web I tried to rewatch a youtube video and froze again. Its starting to frustrate the **** out of me, missing my windows right now, still love the mac, but wish it'd work. Calling apple tomorrow

same problem

1. Put 2011 21.5" imac to sleep

2. Wake up imac

3. Start youtube video playback

4. Computer freezes, sound still plays, can move mouse cursor

5. Do hard reboot of computer

Here is my solution to this issue. Granted this is not the best solution, but a stop gap until Apple Corrects this in a future update.

Go to System Prefrences and select Energy Saver. Set your computer to slepp to Never. After two days of working with this issue with an AppleCare specialist, this is the solution. I believe that something is getting mucked up after the computer wakes from sleep mode and causing the freeze or lock up. These are the steps I have taken thus far.

• Reinstalled Lion
• Emptied my Library, User Library, & System Cache
• Reset the PRAM
• Run in Safe Mode
• Repaired Permmisions
• Repared the Disk
• Switched iTunes to 32-Bit Mode

The other alternative is to downgrade back to Snow Leopard or install Windows 7 on a Boot Camp partition (JK).

This is a certain show stopper for Lion.

Unfortunately the solution with the screen saver didn't helped my 27" iMac 2011, OS X Lion neither did the installation of flash 10.7 beta. Things getting worse with every forced restart. The only thing which made things better (post bone the freezing) was the deleting everything in logging items Accounts preferences (an idea from kisuke3 https://discussions.apple.com/thread/3198677?start=15&tstart=0).

Repairing permission I got the a SUID problem message that this file was changed and coudn't be repaired:

system/library/coreservices/remotemanagement/ardagent.app/contents7macos/ardagen t

Maybe this gives a hint?

Thank for all the advices I would be completely lost without.

If I use my imac as a external HD (T) and work with my Powerbook OSX 10.6 it freezes my PB after awhile. This is so bizarre.

I have the same problem on 27 " iMac model12,2 i7 4 Go SMC 1.72f1 running Mac OS X 10.7 (11A511).