IMac Freezes Periodically During Screen Saver Only

I own a late-2006 Intel-based iMac. Over the last few months, I've noticed that the iMac freezes when the screen saver is running. This doesn't happen all the time, and it doesn't matter what screen saver I use. (None of the screen savers is a third-party.) The iMac doesn't freeze at any other time.
Any ideas?
- Keith
P.S. I'm running Snow Leopard right now, and it happens even with Snow Leopard, just as it did with plain ol' Leopard.

Your iMac has a dedicated Graphic's chip (GPU), while some of the Late 2006 17" iMacs had a GMA 950 graphics processor with 64MB of DDR2 SDRAM that shared with the main memory. To check which Graphic's chip you have go to: Apple > About This Mac > More Info and in the Hardware section select Graphics/Display.
If you would like to monitor the temperature of your GPU, CPU, HD and Memory check out the iStat Pro widget > http://www.islayer.com/apps/istatpro/
The main reason I suspect the lack of RAM over an overheating GPU is because you only reported a problem with the Screen Saver and not with other intense graphic's like movies, videos or games.
Please let us know how you make out with the RAM upgrade.
Dennis

Similar Messages

Freeze during screen saver

Gang,
I recently migrated from a G4/733 running OS 10.2.9 to a 1.9 iMac G5 running 10.3.4. This new machine sometimes freezes after the screen saver has been on for a few minutes. It's done it with the Cosmos and Nature Patterns sets. I don't think it has happened with the 2006 World Book set, but I haven't used that one for long.
I've had a handful of minor annoyances, but this one is worse because it causes me to have to shut the computer down using the power button.
I found this thread: http://discussions.apple.com/thread.jspa?messageID=742697&#742697
The first post implied that this was a noted problem on earlier G5s, but I haven't found earlier references to it, and that thread was locked so it isn't clear to me whether it's been resolved.
Any news on this problem? I stopped using screen savers a long time ago when CRTs got to a certain refresh rate, but I think they're recommended for these LCDs--not sure. I don't want to risk screen burn-in, especially since I do leave it running for stretchs of time playing music in iTunes.
Any advice appreciated!
_dennis

Hi, dennis.
I think the problem to which the archived (you noted locked) thread was referring is Power Mac G5 (Late 2004) 1.8GHz models stop responding randomly. That was specific to the Power Mac G5, not the iMac G5.
With LCDs, sleep or shutdown are preferred to screen savers for extended periods of inactivity. See "Screen Savers: Using With Liquid Crystal Displays." I'd recommend you set the Display Sleep to a short inactivity period, e.g. five minutes, in Energy Saver preferences vs. using the screen saver.
As to the specific problem you've noted, freezes and hangs often have causes similar to kernel panics: the basic troubleshooting and hardware testing steps would be the same. See my "Resolving Kernel Panics" FAQ.
As far as general iMac G5 troubleshooting goes:
1. The first thing I would suggest is ruling out potential hardware problems. Run the Apple Hardware Test that came with the computer. Instructions for doing so will be found in the hardcopy manual that accompanied your computer.
2. Check the diagnostic LEDs, a feature of your iMac G5. See "About the iMac G5 diagnostic LEDs."
3. If your iMac G5 will not turn on, see "iMac G5: Troubleshooting when your computer won't turn on."
4. See also the new iMac G5 Support site.
5. Check the iMac G5 Discussions for similar reports from other users.
6. As a general check, run the procedure specified in my "Resolving Disk, Permission, and Cache Corruption" FAQ. Perform the steps therein in the order specified. In your situation, I'd consider it a long shot, but it will determine if there are any issues with some "common troublemakers."
7. If the computer is either under warranty or covered by an AppleCare Protection Plan, don't hesitate to take advantage of your warranty and contact AppleCare.
Good luck!
Dr. Smoke
Author: Troubleshooting Mac® OS X
Note: The information provided in the link(s) above is freely available. However, because I own The X Lab™, a commercial Web site to which some of these links point, the Apple Discussions Terms of Use require I include the following disclosure statement with this post:
I may receive some form of compensation, financial or otherwise, from my recommendation or link.

Just bought a new iMac, I am in screen saver mode and have forgotten the password ?

Just bought a new iMac, I am in screen saver mode and have forgotten the password ?

This link will tell you exactly how to reset your password
http://support.apple.com/kb/HT1274
In OS X Lion or later, you can reset your user password with your Apple ID.
In Mac OS X v10.6.8 or earlier, follow these steps to reset a password when there is only one administrator account on the computer, or if the original administrator account needs a password reset. "Original" administrator account refers to the one that was created immediately after installing Mac OS X. If the original administrator password is known, that administrator account may be used to reset the passwords of other administrator accounts using the steps described above. These steps require an optical drive; if your Mac does not have an optical drive and you have a Mac OS X v10.6 Install disc, see below.
Start up from a Mac OS X Install disc (one whose version is closest to the version of Mac OS X installed). Usually, you can start from the disc by putting it in your computer, restarting, and holding the C key. Or, put it in the computer and click the Install or Restore icon you see in the disc's main window (after which the computer will start from the disc without you needing to hold C). Or, you can use Startup Manager or the Startup Disk preference pane to select the Install disc.
Choose a language, click the arrow button to continue,
Mac OS X v10.6 or later: Choose Password Reset from the Utilities menu.
Mac OS X v10.5 or v10.4: Choose Reset Password from the Utilities menu.
Mac OS X v10.3: Choose Reset Password from the Installer menu.
Tip: If you don't see this menu or menu choice, you're probably not started from the disc yet.
Note: The default keyboard layout is U.S. English while started from the installation disc. If you use a keyboard layout other than U.S English, use the Input menu (the flag icon on the right side of the menu bar) to select the desired layout before typing a new password.
Select your Mac OS X hard disk volume.
Select the user name of your original administrator account.
Important: Do not select "System Administrator (root)". This is actually the root user. You should not confuse it with a normal administrator account.
Enter a new password.
Click Save.
Click the red button in the upper left corner to quit the application.
Choose Quit Mac OS X Installer... from the Mac OS X Installer menu.
Click Restart.
After following these steps, you'll want to also follow the steps in this article.
Mac OS X v10.6: Resetting the original administrator account password on a Mac that has no optical drive
These steps require a second computer that has an optical drive.Note: If the second computer is a Mac, make sure Mac OS X v10.5.3 or later is installed. If the second computer is a PC, make sure the DVD or CD Sharing Update 1.0 for Windows is installed.
Open "Remote Install Mac OS X" from the Utilities folder.
Follow the onscreen instructions.
For more information, see Sharing DVDs or CDs with Remote Disc.

IMac Freezes at white screen during startup

Hello,
I was off of my iMac for an hour or two so my screen saver when on. I went to wake the computer and it was frozen. I tried using the keyboard and mouse to wake up the computer from the screen saver, but it would not work, so I powered the iMac down manually from the button on the back. I let it sit for 15 minutes, then I tried to start the computer up again. Now at start up, I get to a blank white screen with the spinning moving pin wheel, and that is it. Any suggestions?

You could try to use SafeBoot mode on startup, essentially you'd hold the Shift
key down on startup, perhaps you may need to login after waiting quite awhile,
then continue holding the shift key down until you see a traditional desktop.
And then use Disk Utility to verify HDD, & repair disk permissions.+ Restart.
Or if you have a system install-restore DVD, boot from that and have the
Installer's version of Disk Utility check verify repair the hard disk drive.
It can also repair disk permissions, too, from the booted version of D.U.
Then when it is done, choose the startup disk from installer menu options.
The DVD should eject, but if not, it should be ignored as a boot volume
after you've chosen the Mac HD as a boot system.
PS: If your computer is now running a system later than Snow Leopard,
where no DVD would be needed if it has a Recovery partition in the HDD
then you could see about booting into Recovery (command + R) to access
the later system's OS X Utilities, and choose Disk Utility to check/repair, etc.
These may help.
Good luck!
edited

Os x 10.8.3 freezes when changing screen saver

I recently installed 10.8.3. One of the glitches is that when I attempt to change the screen saver, my computer freezes. Is there a fix for this?

try this - not sure if it will work for you but it's worth a try.
open disk utility - verify your disk permissions - repair if errors are found then restart your macbook once the repairs are done.
see if that changes the way your macbook responds to changing your screen saver.

Help: my iMac suddenly has a screen saver that i don't recognize, and processing has slowed to a crawl...

When I try to awaken the computer, the screen saver (a changing series of neon-colored rings and dots) does not immediately disappear. It can take a full minute for it to go through different displays before it goes away and is replaced by my desktop. And even after I get my desktop back, it takes forever for applications to launch, and even to type simple words into the google search bar. I type, and then have to wait for the words to appear. Is the appearance of the screen saver and the slow processing a coincidence? If not, what can I do to remove the screen saver (and solve the problem)?

How large is you HD and how much space do you have left?

Output rhapsody during screen saver mode

HP G62 Notebook PC, S/N: [Personal Information Removed], P/N: WQ760UA#ABA, Windows 7
I stream rhapsody from my notebook to my avr. When the screen goes blank in screen saver mode it stops outputing rhapsody. I am connected with a hdmi cable. If the cable is not connected and I am using the netbook's speakers and the screen goes blank it keeps playing.

It never has for me ... but you may have a different operating system, different version of Lightroom, different screen saver, different upload destination, different upload plug-in, or different something ...
It sure would help if you told us those details, and the full text of the error message (verbatim, word-for-word, leaving nothing out) and any other information that might be relevant

IMac Freezes on blue screen during startup after installing itunes 9.2

I let iTunes update to 9.2 today on my 27" iMac quad and when it restarted itself it froze on startup at the blue screen. The blue screen switches between two different shades but never exits that loop. I CAN boot in safe mode (which is what i'm doing right now).
Thus far i've tried:
- reinstalling itunes
- resetting my pram
- uninstalling itunes
- removing itunes startup app
I still cannot boot normally. Help!

You might try booting from your install CD and running disk repair in Disk Utility.

IMAC freezing, hang during startup, loud noise coming out from the speaker

I am using the iMAC i3 Intel based which i bought it just a month ago
Last week it hang, freeze just like that without me launch any application just yet
I hold the ON button for a restart, and it freeze during the startup
One more thing, sometimes when it freeze, there's a noise coming out from the speaker ( just like there is no signal from the TV )
Already sent it to the Apple Service Center but they tell me it is free from any error, but by the time i bring it back home, not even 12 hours, it freeze again just like that with loud noises coming out from the speaker.
Btw did i mention, sometimes there's also a screen distortion
Please somebody help me

I've experienced similar symptoms to the original poster's description. I have an iMac 27" 2010 model. This may be related to the following:
I've looked on numerous forums regarding the freezing problem I was having. This problem would arise on a wide range of systems.
Symptoms included but were not all always present - usually when I am loading the system with games/heavy load processes:
- Full system freeze, screen still on.
- Loud cracking noise coming from speakers (relative to what volume was at when the freeze happened).
- Computer asleep but I cannot wake up unless hard reset with power button.
- My screen backlight was also damaged (permanently dimmed) near the left side, and progressively got worse over time. This was fixed (replaced LCD 27" display $600+ and covered by my creditcard extended warranty)
Basically, what I've come to realize which has not been well documented as far as I could find relating to this problem - is that the system is overheating and causing these freezing errors (and LCD damage in my case). Prologned occurances could result in different system part failures.
How do you fix the overheating problem? Give this a try, it's worked so far for me and I've actually been able to continue video/photo editing without having this annoying freeze.
Search for and download 'iStat Pro' (widget addon that lets you monitor your system temperatures... compare it before and after the fix)
Search for and download 'SMCFanControl (a great little app that allows you to change your system fan speeds) - I did not know this was possible, and have never heard the fans go this high when it was being run automatically by the system. The fan's are obviously louder when set to max, but is well worth the system cooling results.

IMac Freezing Up/Blue Screen

If this was posted in the wrong forum, please move.
Sunday evening, my iMac G5 started freezing up a lot. I was forced to keep restarting my computer. Originally, I thought it was due to Firefox 3 seeing how I just downloaded it a few days prior. I ended up deleting Firefox, but the problem only got worse. After looking online and trying such things as repairing the permissions, I gave in and did a disk install (while keeping network settings and files). Disc 1 install went fine, but everytime I tried to install the contents of disc 2, it would freeze. I decided to just attempt to do a full re-install losing all of my contents of my computer. Finally, while starting in Safe Mode, I was able to finish installing disk 2.
However, now I can't even get on my computer without it going to a plain blue screen (NOT the default wallpaper) and either the spinning pinwheel (I assume it was freezing up) or a curser. There wasn't any dock or any icons most of the time. Occasionally, it does take me to my default wallpaper, but it freezes up before the entire dock shows up.
Everything seems to work fine in Safe Mode, but trying to log into the normal mode always gets me to the blue screen or a frozen screen.
My S.M.A.R.T. said that it was verified. Meanwhile, through the install disk I have been in Disk Utility and I have ran a disk repair and repair permissions. The problems continues though.
I've presented my problem to another message board which had the general thought that my HD was dying and I was in need of a new one. However, I have conflicting reports as another person is saying that my HD is not dying, especially considering the S.M.A.R.T. was verified.
Right now money is tight, so I can't just easily go out and buy a new HD. So I'd like to try anything before giving into that. Any help would be greatly appreciated.
Details:
17-inch iMac G5 (Ambient Light Sensor)
1.8 GHz PowerPC G5 processor with a 17-inch screen
Owned since Sept 2005

Hello and Welcome to Apple Discussions ...
If you haven't tried this yet... grab your system restore disk(s). Make sure your Mac is shut down. Now, while holding down the C key, press the power button and insert the disk. Keep holding the C key until you see the Apple logo on the screen. Now, an Installer window will open... ignore that and go up to the Menu and click Utilities/Disk Utility. DU will launch. Select MacintoshHD in the panel on the left, make sure the First Aid button is selected and click Verify Disk. I'm not talking about the S.M.A.R.T status.. this is going to check to see if there are errors on the drive. If DU reports errors, click Repair.
Now, you can't use Disk Utility from the Application folder on the drive, you can only Verify and Repair the disk from Disk Utility on your restore disk(s). If Disk Utility reports errors but cannot repair them then you might want to look into a good disk repair utility such as DiskWarrior
www.alsoft.com or TechToolPro www.micromat.com Neither are expensive.
I understand how important your Mac is to you and I hope this helps.
Carolyn

Imac freezing up and screen dissolve issues

Hi all,
My imac intel keeps freezing up for no reason and then won't let you force quit anything.
It still seems to do things in the background like import cds to itunes and download items.
Sometimes it also freezes and then the screen slowly dissolves to bright white and then restarts itself.
Has anyone come across this before.
The imac is about 6 years old.
Thanks in advance.

If your Mac ame with an Install Sisc, AHT hw test should be on one of them.
One way to test is to Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, Test for problem in Safe Mode...
PS. Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive
Reboot, test again.
If it only does it in Regular Boot, then it could be some hardware problem like Video card, (Quartz is turned off in Safe Mode), or Airport, or some USB or Firewire device, or 3rd party add-on, Check System Preferences>Accounts>Login Items window to see if it or something relevant is listed.
Check the System Preferences>Other Row, for 3rd party Pref Panes.

IMac freezes at login screen for file server

The machine: iMac (lampshade), OS 10.3.9
The symptom: During the boot/login sequence, the machine locks up at the login screen to the file server.
If I disconnect the network cable during the boot sequence, it will error but not freeze; I can later reconnect the cable and login without a problem.
Any ideas?
James

You may want to look at this similar post:
http://discussions.apple.com/thread.jspa?messageID=690609&#690609
Heres what Mac Help said.
Open System Preferences and click Startup Disk.
If necessary, click the lock icon and type the name and password for an administrator user.
Click the icon of the system folder or system volume that you want to use, then click Restart.
IMPORTANT: When selecting a network startup volume, be sure you select a valid network startup volume and not a network install image. Choosing a network install image reinstalls your system software and may erase the contents of your hard disk. A standard network volume icon appears as a globe and Mac OS X system folder. When you select a network volume icon, a message appears in the Startup pane describing the volume. A network install icon appears as a globe with downward pointing green arrow.
Another way to select a startup disk is to hold down the Option key as you restart your computer. You'll see the available startup disks and can select one.
If your computer is on a network and a network startup volume is available, you can start up from the network startup volume by holding down the N key as you restart your computer.

IMac freezes plus pixelated screen when restarted.

My iMac has been freezing and when I restart it the screen goes into black & white pixels after the grey start-up and blue screens. If I soft boot and hold down the D key when starting it works okay. Any ideas? I have an iMac 2.46HZ Intel Core 2 Duo 4GB 667 MHz DRR2 SDRAM. Please keep any help as simple as possible since I'm not very tech savy. Thanks!

I think it's a GPU issue. GPU problems appear and disappear, so I'm not surprised that your iMac sometimes works correctly.
I recommend you to take the iMac to an Apple Store or reseller. The GPU is soldered onto the logic board, so this may be an expensive repair

Imac freezes with gray screen after mavericks update

I was updating my imac system and it is frozen in a gray screen, like it is restarting.
It's been twenty minutes and it didn't restarted.
What can i do if it don't restart anymore?
All my work data is on that imac.

Take each of these steps that you haven't already tried. Stop when the problem is resolved.
Step 1
The first step in dealing with a startup failure is to secure the data. If you want to preserve the contents of the startup drive, and you don't already have at least one current backup, you must try to back up now, before you do anything else. It may or may not be possible. If you don't care about the data that has changed since the last backup, you can skip this step.
There are several ways to back up a Mac that is unable to start. You need an external hard drive to hold the backup data.
     a. Start up from the Recovery partition, or from a local Time Machine backup volume (option key at startup.) When the OS X Utilities screen appears, launch Disk Utility and follow the instructions in this support article, under “Instructions for backing up to an external hard disk via Disk Utility.” The article refers to starting up from a DVD, but the procedure in Recovery mode is the same. You don't need a DVD if you're running OS X 10.7 or later.
b. If Step 1a fails because of disk errors, and no other Mac is available, then you may be able to salvage some of your files by copying them in the Finder. If you already have an external drive with OS X installed, start up from it. Otherwise, if you have Internet access, follow the instructions on this page to prepare the external drive and install OS X on it. You'll use the Recovery installer, rather than downloading it from the App Store.
c. If you have access to a working Mac, and both it and the non-working Mac have FireWire or Thunderbolt ports, start the non-working Mac in target disk mode. Use the working Mac to copy the data to another drive. This technique won't work with USB, Ethernet, Wi-Fi, or Bluetooth.
d. If the internal drive of the non-working Mac is user-replaceable, remove it and mount it in an external enclosure or drive dock. Use another Mac to copy the data.
Step 2
If the startup process stops at a blank gray screen with no Apple logo or spinning "daisy wheel," then the startup volume may be full. If you had previously seen warnings of low disk space, this is almost certainly the case. You might be able to start up in safe mode even though you can't start up normally. Otherwise, start up from an external drive, or else use the technique in Step 1b, 1c, or 1d to mount the internal drive and delete some files. According to Apple documentation, you need at least 9 GB of available space on the startup volume (as shown in the Finder Info window) for normal operation.
Step 3
Sometimes a startup failure can be resolved by resetting the NVRAM.
Step 4
If you use a wireless keyboard, trackpad, or mouse, replace or recharge the batteries. The battery level shown in the Bluetooth menu item may not be accurate.
Step 5
If there's a built-in optical drive, a disc may be stuck in it. Follow these instructions to eject it.
Step 6
Press and hold the power button until the power shuts off. Disconnect all wired peripherals except those needed to start up, and remove all aftermarket expansion cards. Use a different keyboard and/or mouse, if those devices are wired. If you can start up now, one of the devices you disconnected, or a combination of them, is causing the problem. Finding out which one is a process of elimination.
Step 7
If you've started from an external storage device, make sure that the internal startup volume is selected in the Startup Disk pane of System Preferences.
Start up in safe mode. Note: If FileVault is enabled, or if a firmware password is set, or if the startup volume is a Fusion Drive or a software RAID, you can’t do this. Post for further instructions.
Safe mode is much slower to start and run than normal, and some things won’t work at all, including wireless networking on certain Macs.
The login screen appears even if you usually log in automatically. You must know the login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
When you start up in safe mode, it's normal to see a dark gray progress bar on a light gray background. If the progress bar gets stuck for more than a few minutes, or if the system shuts down automatically while the progress bar is displayed, the startup volume is corrupt and the drive is probably malfunctioning. In that case, go to Step 11. If you ever have another problem with the drive, replace it immediately.
If you can start and log in in safe mode, empty the Trash, and then open the Finder Info window on the startup volume ("Macintosh HD," unless you gave it a different name.) Check that you have at least 9 GB of available space, as shown in the window. If you don't, copy as many files as necessary to another volume (not another folder on the same volume) and delete the originals. Deletion isn't complete until you empty the Trash again. Do this until the available space is more than 9 GB. Then restart as usual (i.e., not in safe mode.)
If the startup process hangs again, the problem is likely caused by a third-party system modification that you installed. Post for further instructions.
Step 8
Launch Disk Utility in Recovery mode (see Step 1.) Select the startup volume, then run Repair Disk. If any problems are found, repeat until clear. If Disk Utility reports that the volume can't be repaired, the drive has malfunctioned and should be replaced. You might choose to tolerate one such malfunction in the life of the drive. In that case, erase the volume and restore from a backup. If the same thing ever happens again, replace the drive immediately.
This is one of the rare situations in which you should also run Repair Permissions, ignoring the false warnings it may produce. Look for the line "Permissions repair complete" at the end of the output. Then restart as usual.
Step 9
If the startup device is an aftermarket SSD, it may need a firmware update and/or a forced "garbage collection." Instructions for doing this with a Crucial-branded SSD were posted here. Some of those instructions may apply to other brands of SSD, but you should check with the vendor's tech support.
Step 10
Reinstall the OS. If the Mac was upgraded from an older version of OS X, you’ll need the Apple ID and password you used to upgrade.
Step 11
Do as in Step 9, but this time erase the startup volume in Disk Utility before installing. The system should automatically restart into the Setup Assistant. Follow the prompts to transfer the data from a Time Machine or other backup.
Step 12
This step applies only to models that have a logic-board ("PRAM") battery: all Mac Pro's and some others (not current models.) Both desktop and portable Macs used to have such a battery. The logic-board battery, if there is one, is separate from the main battery of a portable. A dead logic-board battery can cause a startup failure. Typically the failure will be preceded by loss of the settings for the startup disk and system clock. See the user manual for replacement instructions. You may have to take the machine to a service provider to have the battery replaced.
Step 13
If you get this far, you're probably dealing with a hardware fault. Make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

IMac Freezes at Login Screen

When I reboot my IMac, it gets to the login screen and freezes. The mouse will work, but I cannot enter anything into the password field; after a few minutes, I am able to start typing.
Any ideas?
Joe

jcabaleiro wrote:
When I reboot my IMac, it gets to the login screen and freezes. The mouse will work, but I cannot enter anything into the password field; after a few minutes, I am able to start typing.
If you launch the Console utility you might spot messages around the time of the freezes that could explain what's happening.

IMac Freezes Periodically During Screen Saver Only

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