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

I added a bug report with apple. They have come back to me and confirm it's a known defect. While there is no timeframe for a fix, knowing it's in the system should give us some hope it can be fixed. I'm guessing this will be fixed in the next update as frankly its a pretty poor state of affairs. If I owned this part of the system as a develop manager I'd make sure this was a must have fix.

All the posts here seem to refer to video issues. But, I can't help wondering if this is a wider issue. MacBook Pro i7 on OS10.7 Lion here. I am getting the system freeze when I leave the computer for some time.

The interesting point is that the symptoms seems the same:

Mouse movable

No clicking available.

Unresponsive

Requires hard reboot.

With me it doesn't seem to be related to any particular program. What I do notice is that windowserver and fseventsd will start using 100% (or more) of the CPU.

My imac is a week old, running osxlion and freezing me out 3 or 4 times a day. im new to mac and not impressed. this is exactly what i was trying to avoid.

As suggested in this thread, I have gone to Energy Saver in Systme Preferences, and turned sleep to "Never". Early days, but so far, that seems to be a stop-gap fix.

Someone encountered other type of problem too ? I have the freezing on video after sleep but I have problems switching between sessions. The whole system freeze when I am coming back from another session/user. It also freezed the first time I logged into the guest account. Hard reset necessary in each case...

Another theory... On wakeup the MobileMe Sync runs. The various maintenance scripts (Cron scripts) will also run, because the computer was asleep at the time they were scheduled during the night.  Maybe also, updates, snapshots and then spotlight re-indexing are all also going to run.

These combined will be using a lot of CPU for a while.  The advantage of setting the sleep preference to "never" is that the cron scripts etc will run normally in the night and not load the CPU in the morning.

I had a same problem, update of flashplayer to 11,0,1,60 beta seems to  solve it. System runs smooth,  flash crashes som times but only in sandbox. I had no system freeze after this upgrade. Giv it a try

Just add me to the list except I have a 21.5" iMac 2.5 GHz i5 with 4 GB. I purchased it on July 16th. I'm running second monitor. This crap makes me so angry!

Same problem here: 27" iMac i7, Lion, getting frequent lockups - nothing will respond, except mouse moves, but I can't click on anything.  Requires a hard reboot...

10.7.2, which is in the developers hands right now and should be released soon fixes the issue. In the meantime, go to Energy saver settings, change "Computer Sleep" to Never and reboot. It has totally resolved this issue for me.

When the patch comes out, we can all go back to computer sleep mode if we want! I was plagued with this issue and on Thursday I tried this and I have watched a ton of videos without one single lock up.

A PITA? Yes. When people say that it makes the computer useless, that they are taking it back because it's garbage, it is just riduclous. Here is a easy fix, costs you nothing, and you will be asked to live this way for about a week. Get a grip people. There are far bigger problems in the world.

Janimac62 ... thanks for the update.

Just so I'm clear, are you leaving your Mac running all the time and is there a difference between a system initiating sleep and a user initiating sleep (if you know)?

Ok this makes no sense. After many freezes mostly video related, I went back to Snow leopard, actually had 2 video crashes on snow leopard. Went back to Lion a week ago just to see what happened...not a single crash.

watched many videos.

I did notice last crash Parallels was running I have not run it since. I will wait a few more days and try running Parallels and see what happens.

imac 27 i7 8gb ram 2010

Is this graphics update any help?

http://support.apple.com/kb/DL1389

Same here , iMac 21.5"

The ONLY thing anyone can do right now is just go back to Snow Leopard. I did that a few days ago  and have had no problems that Lion currently has with freezing etc. I know it ***** that we have to wait for Apple to fix this but if your like me , I had enough of the Lion issues and am going to sit and wait for them to fix this. I have called into apple support four times and nothing has helped btw. There has to be an update soon..