My current findings on iMac 21,5" mid 2010 having 10.7.3: Video watching e.g. via VLC player on secondary screen -> occasional jams for video window. Few other programs running, CPU usage very low, having 8 GM RAM. No permanent jam/freezing thou. Probably related to https://discussions.apple.com/message/18144133#18144133 so common nominator here: Lion. Official Apple service confirmed that "Lion has got some issues" and said that hardware can be checked. Maybe it's just graphics hardware + drivers + Lion = no joy. Very disappointed this time and future will show is this our last Apple product (now having iMac * 2, MBPro, AppleTV, TimeCapsule).. cannot afford high price with low quality
iMac 27 2.93 i7, 16GB ram. Screen goes black randomly after Lion upgrade 10.7.3.
Finally found a quick solution to avoid a restart after a blackout.
When it goes black the CPU and system is still running, but can't do anything without force restart. Mirrored monitor stays on and i can work, but its a pain. The blackout is intermittent and i can't recreate the issue. Have restarted, Reset PRAM, SMC, prefs, privledges...everything.
I found this and it worked for me to get the screen to come back on without restart:
Shift+Control+Eject key. This forces the system to switch back to the inegrated graphics and not the nvidia drivers, which is causing the blackout.
I have the white plastic iMac 24" which was working beautifully on SL until I updated Safari to 5.x and started seeing a few problems. Then I upgraded to Lion and it down hill from there.
Freezes and other random events. It continues to deteriorate. I have started getting kernal panics. Today one finder window turned into a patchwork of random patterns while another looked like each letter had been redacted.
I went to do something to a Thunderbird email and the window vanished. I clicked around and piece by part it started to reappear. Then all the tabs from Safari vanished. Later Safari crashed and I was not even looking at anything - and it continued to crash over and over. I started deleting plists, history, caches, etc, piece by piece until it finally came back to life.
I can watch videos fairly well with Safari or quicktime, but when I use Firefox, things go crazy. I have deleted everything related to Firefox and reloaded it and it is no better.
I would like to go back to SL, but do not want to lose all my emails. (I have read that it can be done, but not easily)
I thought I would buy a new 27" iMac and surely that would work - but then I read this very long thread.
I contacted Apple and asked if I could get a new iMac with SL instead. They said no, but maybe with a refurb.
So I stuggle along with my old iMac hoping someday my fix will come.
Maybe Jobs took the secret of good, solid software with him.
Does anyone have a newer 27" iMac that works flawlessly on Lion?
The 'best' thing you can do is get away from LION as fast as you can. It's a hopeless mess with no solution in sight. In the interest of preserving your hardware, get back to Leopard.
Why Leopard? Snow Leopard (10.6.8) is known to have the same symptoms as LION. That's where my troubles began.
It sounds like your iMac dates from around 2007, so it may have shipped with Leopard originally.
What I did was this: I used Disk Utility to create a smallish 50GB partition on my HDD onto which I installed Leopard using the DVD that came with my machine (2008 iMac 20"). I use Leopard as the boot partition, while the LION installation remains---ready to be updated whenever updates are available (and, perhaps, the SOLUTION).
All my files are located on the LION partition, but they are easily accessible from Leopard. Leopard has full read and write capability with regard to anything on the LION partition.
Doing it this way is less inconvenient than wiping your entire HDD and re-installing Leopard or SL (and then restoring all your files and apps from a backup).
You can't really afford to keep cutting the power to your iMac after every freeze (and they will keep coming---no matter what!). It's not good for your hardware and your hard drive may fail as a result.
The iMac appears to be form 2006 - how time flies. I do not even have 50KB to spare although I oculd delete a lot of pictures that I have doubly backed up.
I have another problem besides my iMac going crazy the last few days. I dropped a Netflix video in the drive without checking it first. Turned out it was broken and took out my optical drive. So I have to take it in for repairs before I can revert. I like you idea though and thanks for the suggestion. I acknowledge your comments on the hardware and disk drive and have backed everything up. I am hoping that the new iMac comes out soon, although the Lion issue would remain.
As far as my problems, in addition to the documented Lion issues, I think I have a ramdom memory writer. Programs like Safari and Mail randomly start crashing and can't be reloaded without crashing until the computer is restarted. Then safari would not display the reading list or the history / bookmarks until I restarted. It goes on.
But then this morning all is (at least temporarily) working just fine.
Thanks for the comments.
if the iMac was bought in 2006, then it came with Tiger. You probably don't want to go back that far (to 10.4) if you don't have to. I assume you purchased Leopard and/or Snow leopard DVD discs later on. You could use whichever install DVD you like.
The 50GB was just a suggestion. You could make the boot partition as small as 15GB.
I have a feeling that the next product-refresh for iMacs will likely not have the LION freezing problem. The latest Mac Mini and Macbook Air were issued at the same time as Lion (and only ever ran with Lion) and I've never heard of anyone having Lion problems with those models. The current batch of iMacs predate Lion by a few months and have quite a lot of trouble. Most posters on this thread have new iMacs.
In fact, the next iMacs may ship with Mountain Lion instead.
I have started to get the corruption too, on my 11,3 Mid-2010 27" iMac.
I don't have Lion installed, and instead have stayed with Snow Leopard. So it's not a product of Lion, necessarily I would say.
I'm getting corruption like:
or more typically, the coloured squares that cover the screen:
I've had 2 freezes recently, which, as others have described, are weird because it's like the computer/HD are all still doing their job, but the mouse is just unresponsive. This has taken place twice after opening VWWare, the latest after I was installing Ubuntu.
According to iStat, the GPU related temperatures are about 53C and that's not particularly unusual according to my recollections.
EXTREMELY annoying. Luckily I stil have AppleCare so will see what happens there.
I've managed to stabilize my iMac by only running Safari and iTunes. I can't let it go to sleep with out the computer crashing. Restarting the computer can take anywhere between 2 and 4 hrs. but once it starts I find I can use my address book, safari and iTunes (As I’m not using the computer anymore I’m not sure what other apps can run). I've had to migrate my work off of the iMac and onto a Dell laptop (I need a few Windows apps for my business and with the small screen on my Macbook pro there is no point). As I no longer use the iMac for anything, I have been just playing music from my iTunes library to see how long it will run before it fails again. In the evenings, I'll play movies from my iTunes library as another test. The music and movies both freeze from time to time.
Looks like I no longer have the original discs! At one point I was able to boot from a LION dvd I created but that is no longer working.
I am not able to boot into recovery mode. This has worked in the past but stopped working after I reinstalled LION from booting the LION DVD.
I understand that it is difficult to be definitive but I don't think I have a hardware problem. My iMac has always run in an air conditioned room with conditioned power.
My iMac is late 2009 27" with the Intel i5/ 2.66GHz chip with 8GB RAM.
My mistake it tossing out the original disks!! I have two MacBook Pros, a Mac Mini, and a 27” iMac. I think I kept one copy of the disks and tossed the rest not knowing they were specific to the computers. In any case, I can no longer boot from the DVD so not sure it matters.
One of my MacBook Pros is still on Snow Leopard (I was not able to upgrade to Lion because it only has 1GB of RAM) and I am seeing very long delays in the computer displaying the login page after boot up. At this point I turn the computer on and basically walk away. I check back in an hour or so and if its running then I can use it, otherwise we wait! My other MacBook Pro is on LION and as far as I can tell, I’m not experiencing any issues. My Mac Mini is also on Lion and not experiencing any trouble.
I’ll be taking my iMac into an Apple repair store next week.
@ iDik: I also have had stability for about a month now--something I haven't had in maybe two years. I don't know what exactly to attribute it to, but I have done only two things: 1) disabled Java as you did--that much we have in common 2) readjusted sleep time by separatibng display sleep (c. 5 min.) from computer sleep (c. 1 hr.)
I actually did #2 before #1, and I noticed immediate improvement. Again, I have no idea why, but things are decidedly much better.
Latest update from my iMac 27in mid 2011 with Lion OS
After going to the Apple store 3 times (3 hrs driving from my current home)
1st time: Geniuos guy said and did: Just do regular permission reparation
2nd time: Geniuos guy said and did: You need you HD replaced
3rd time: I said: Still failing did you guys did the stress test you said you do when you replace a part?...
The "stress test" (according to what they say) they open lots of browsers playing videos, itunes, etc etc... basically they stress the system...
THEY didn't do that AFTER replacing the HD... they just did it before and asume that was the problem... replaced the HD and WRONGLY didn't do it again Just in case...
Anyways... after picking up my iMac after its HD replacement... my iMac failed right away at home... "GREAT" I though... So I went back to the store and told them the whole story and I even told them.. I have read in the discussions forums about this issue and I'll recommend you guys to keep a close look in the logic board.... they were blaming the RAM long story short... was the logic board... they called my bf to confirm the iMac was ready, and my boyfriend asked them if they did an AFTER stress test...they say yes sooooo... picking it up this monday coming and I'll keep you posted!...
I bought a 27" iMac with Lion in Feb and have had mixed problems since the beginning - relatively small, but irritating. I've resolved most of them and know a LOT more about the computer than I ever thoguht I would. Has kind of soured me on Apple quality though and am having a hard time persuading myself to accept the changes in Lion, but that's a different issue.
Yesterday, for the first time, right in the middle of working, the screen went totally black-not a hint of grey or color anywhere. PANIC! Finally figured out that I needed to do a hard reboot and have learned more in the three times more that it's crashed in the past 8 hours.
Only difference is that I purchased and used Clean My Mac - could that be the issue?
I save and back up my work consistently and with multiple formats, so I'm not (too) worried about losing work, but it's a real bother to get paralyzed like that.
Any more ideas?
If the machine is still running but the screen is black, the best and easiest way to get it back is to hold shift+control and press the eject key on the keyboard, wait a second then press the spacebar or any key and the screen will come back. This forces the operating system to use the integrated video instead of the card. It's a pain. Ours started doing it after the Lion updates to 10.7.x and now its doing it on two new iMacs that never had the issue.
Sometimes it will go black 5-10 times a day, or even in a hour, other times it will be fine for days. No rhyme or reason to it.
see info here:
this is better than a hard reset until Apple finally fixes it. I'm assuming its software, since we never had the issue until Lion and it's updates.