Imac g5 repeated reboots after startup

My imac g5 has started rebooting on its own. Sometimes after startup and sometimes while it starts up and other apps have loaded. What now??

Try the following:
http://docs.info.apple.com/article.html?artnum=301733 iMac G5: How to Reset the SMU (iMac G5, the iMac G5 (Ambient Light Sensor), and the iMac G5 (iSight)).
http://docs.info.apple.com/article.html?artnum=2238 Resetting your Mac's PRAM and NVRAM

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My iMac freezes up shortly after startup.

My iMac freezes up shortly after startup. I can't move the mouse or use the keyboard. I have to manually shut down several times before it would work.

Hi patrickbryant,
Thank you for participating in the Apple Support Communities.
If your iMac is becoming unresponsive when you start up, I recommend trying to boot into Safe Mode as well as using Disk Utility to verify your hard disk. You can find these steps outlined at this link:
Resolve startup issues and perform disk maintenance with Disk Utility and fsck - Apple Support
Best Regards,
Jeremy

IMac noisy 30 mins after startup

Hi all, I have a 27" Imac, model no A1317. 30 mins after startup, it becomes constantly noisy and is very warm on the left upper back.
Any suggestions would be much appreciasted.

I would recommend doing 2-3 SMC resets back to back. Also if your machine is older than 2-3 years you may have a lot of dust buildup in the air intake. You can remove the RAM cover and vacuum out any dust buildup. DO NOT blow air in, only vacuum out.

My imac screen is flashing after startup?

I may have a problem with my imac's screen flashing around the dock right after blue screen it shows up.
The dock will flash for a 1sec or 2sec and thats it.
Do i need to test the memory because i did install Hynix 2 X 2GB PC3-8500S DDR3 and they where from a macbook pro?
Will i need to take them out and leave in 2 original sticks then restart the imac to see if it corrects the problem?

A screen flash is not related to RAM. It's some other issue, which could be software or hardware related. You can start by doing some basic trouble shooting including restarting in Safe Mode and doing both a SMC and PRAM reset. It's OK to do each of these actions multiple times and it may be necessary to do them multiple times. If they don't help you can try some other things which we won't address yet.
iMac
SMC & PRAM Resets
SMC RESET
Shut down the computer.
Unplug the computer's power cord and all peripherals.
Press and hold the power button for 5 seconds.
Release the power button.
Attach the computers power cable.
Press the power button to turn on the computer.
PRAM RESET
Shut down the computer.
Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.

IMac won't reboot after system restore from Time Machine

I just installed a wacom intuos pro tablet on my imac running snow leopard. The system clock reset to 1st Jan2000 and system prefenerces were no longer accesible. I performed a system restore from my time machine but now can't reboot. The restore completed succesfully (or so the it told me). When i restarted the imac i got the usual 'bing' followed by grey screen and spinning wheel swiftly followed by a light blue screen with the cursor in the top left hand corner.
There is sat for an hour befoe I switched off and tried again......same result.
The installation disc is still in the optical drive.
Any advice please on how to remidy this?
Thanks

I have/had a similiar problem. What I did was reset the SMC and PRAM. You can also do a safe boot. For the PRAM, I had to do three times, and my computer finally booted up. Afterwards I verified my disk and repaired my permissions. So far so good. I guessing that Spotlight needed to re-index the system.
http://support.apple.com/kb/ts2570

Imac will not reboot after loading apple software update

I downloaded apple update software on imac air but it will not reboot. Just the apple and spinner. Never gets to sign in.

Mac OS X: Gray screen appears during startup

Bondi iMac shuts down immediately after startup button light turns green

Is my Bondi blue baby (purchased at the midnight launch of the original iMac) finally dead?
When I push the startup button, it glows amber and the startup chime sounds. A few seconds later, the button glows green for an instant, and the power shuts off. The button then won't do anything unless I unplug the power supply for a few minutes and plug it back in.
I have tried using a paper clip to push the reset button, but to no avail. Also tried zapping the PRAM, as well as starting from a CD, but neither helped.
I know the unit has little value other than the sentimental, but my mother-in-law (who inherited it from me) is used to it and is hoping that I can bring it back to life.
Is there anything else I should try before carting it off to the recycling depot? Thanks!

Hey H S,
This is from the service manual for the Bondi:
"The battery on the logic board controls the stored system settings,
such as date and time. It is important to note that the battery does
not affect power at startup."
However this is from page 11 of the s. manual for the 400, SE and DV:
"7 Press the power on button on the front of the computer again.
If the computer won’t start, go to the next step. If the
computer does start, you may have a *bad battery*."
So I always check the battery. Altho' all the won't start cases I've seen where the battery was the cause did not exibit the starts up and shuts down symptom.
Also from the manual:
"Resetting the logic board can resolve many system problems (see
the Symptom/Cure tables for examples). Whenever you have a
unit that fails to power up, you should follow this procedure
before replacing any modules.
1. Unplug the computer.
2. Disconnect the cable that runs from the power supply to the
power filter board on the bottom side of the logic board/mass
storage chassis.
3. Press the Power On button on the front of the unit.
4. Remove the logic board/mass storage chassis from the unit.
5. Remove the battery from the logic board.
6. Wait at least 10 minutes before replacing the battery.
7. Make sure the battery is installed in the correct +/-
direction.
8. Reassemble the computer and test the unit."
There are protection circuits in the iMac and usually a bad PAV ( flyback and HV caps in particular) are the cause of this particular failure symptom.
Richard
Message was edited by: spudnuty

IMac won't reboot after recent wifi update

27 inch iMac running Lion OSX. Installed the recent wifi update that popped up in software update and now the iMac hangs on the gray boot screen. Ideas?

Try a safe boot. Hold the Shift key down between the start up tone and the Apple logo/pinwheel.
If successful, Go to System Preferences > Startup Disk > Select your MacIntosh HD and restart.
Regards,
Captfred

Please Help: iMac black screens after startup logo + spinning wheel no cursor).

Hi, guys.
I'm in a fair bit of a desperate situation; my iMac's screen seems to shut down every time after the white startup screen. The Apple logo appears, & the progress wheel begins spinning, then after a while - when it would usually then go to the gray login screen - it would, instead, go black. I can tell that the machine is still on (I can still hear it clicking as it does during processing) but I'm unable to determine anything else. Nothing is visible on the screen - not even the cursor - it's as if the display had turned off completely. I'm not sure if the login screen sits beneath that black screen (I have tried to log on by typing my login details in blindly, but even if it does log in, it's hard to determine what state the computer is in without seeing the screen.
I have tried the PRAM reset (holding CMD+OPT+P+R) during both the white startup screen, & the black screen to no avail. It seems unresponsive because I don't hear any additional chimes that I've been told should be heard during a PRAM reset attempt. I can't even be sure that the command is being inputted correctly because the light on my wireless keyboard remains off during the process.
I've tried rebooting over & over again; the results are the same.
The steps that led to the problem occurred thusly:
1 - I was trying to clear some memory from my current session, so I scanned through my active processes, quitting anything which seemed to be eating up considerable amounts of memory.
2 - One particular process I quit was 'launchd' which was functioning under my profile username.
3 - After quitting launchd, all opened apps seemed to close, & it looked like I was forcibly logged off the machine. The screen froze during this point, & I decided to do a hard reboot to log back in.
4 - The problem began after this hard reboot; startup seemed to occur as per usual; white screen > apple logo > progress wheel > and then suddenly, a black screen where the login screen should be.
I've shown a flashlight into the screen while it's black & it seems well & truly like the display has shut down while the iMac continues in the background. I have had issues relating to my screen going black before, but they were random & intermittent; they didn't occur without fail during the exact same time immediately after startup, & could be remedied by using the CTRL+OPT+EJT keys.
I am on an iMac 2010, 27", using I believe Lion OSX. I am unable to recall additional specifications while the problem persists.
Could anybody please help me? I'm quite desperate; I was in the middle of some urgent work that I need to get back to as soon as possible.
Thank you I'm advance to anyone with advice on how I can go about fixing this.
,c.

Gray screen appears during startup

Why does my iMac using Lion reboot immediately after shutdown?

I shut down every night, and for the past several nights my iMac immediately reboots. The only way to solve this is to press the power switch, but if I do that the iMac doesn't reboot the next morning at the time scheduled in the Energy Saver system preference.
Why?

I would reinstall Lion, preferably from scratch if possible.
Reinstalling Lion Without the Installer and Without Erasing the Drive
Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alterhatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the main menu. Repair the Hard Drive and Permissions as follows.
When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the main menu.
Reinstall Lion: Select Reinstall Lion and click on the Continue button.
Note: You can also re-download the Lion installer by opening the App Store application. Hold down the OPTION key and click on the Purchases icon in the toolbar. You should now see an active Install button to the right of your Lion purchase entry. There are situations in which this will not work. For example, if you are already booted into the Lion you originally purchased with your Apple ID or if an instance of the Lion installer is located anywhere on your computer.

IMac freeze after startup, works fine in safe mode

Hello, my Mid 2010 iMac is freezing about 3 minutes after startup. Ive tried booting from the instal disk and repairing it but it didnt work. In safe mode it works completely fine. It similar to some other peoples problem but i was hoping someone could help me, my applecare literally just ran out like 3 weeks ago.

Hi baltwo,
Im sorry but Im new to the community and I don't know how to address users directly. Hence intruding.
It would be kind of you to shed some light on the matter.
I'm running lion 10.7.5 and followed similar procedures but mail downloads every mail again after cataloging and indexing my earlier(snow leopard 10.6.5) mail. More details at https://discussions.apple.com/thread/5373643
It would be great to find a solution as I'm struggling since two weeks.
Thanks,
Abu Suda

Not all users are displayed for log on after a reboot or startup...

Problem summary: Not all users are displayed for log on after a reboot or startup...
This problem only occurs after a fresh start-up or restart. The only users displayed are the initial (admin user) and "Guest". Two other (non-admin) users are not shown for log on.
To work around this problem and get them to log on we have to log on as the admin user, then we can see the other users in the Fast User Switching menu (top right-hand corner of the screen), listed under the current logged on user. After selecting the non-admin user we can log in and use the laptop as normal.
If we lock the screen, use fast user switching or log out all users; all users are available for log in, until a reboot is done; at which point the non-admin users disappear again and we have to log in as the admin user and use fast user switching again.
The laptops are both brand new MacBook Airs. The initial configuration of Mac OS X Yosemite was done using the Apple ID of the purchaser (parent) and then the OS was patched, immediately, through the App store (no further updates available as of the date of this posting). After this Family Sharing was activated and new users set up for the two children who will be using these laptops.
Has anybody else experienced this problem with Yosemite?
Cheers,
David.

David,
Users not enabled for FileVault unlock are only able to log into the computer after an unlock-enabled user has started or unlocked the drive. Once unlocked, the drive remains unlocked and available to all users, until the computer is restarted.
FileVault has to be On.
To Enable the users to be able to unlock FileVault Go to:
System Preferences > Security & Privacy > FileVault ( Tab ) > Click the Lock in the bottom left > Put in your administrator password > Should see an option to Enable Users > Enable User.
Hope that helps,
Weston
Supporting Articles,
OS X: About FileVault 2 - Apple Support

I have a late 2006 iMac that has just started giving me a message to reboot after a black screen comes down slowly from the top top of the screen to the bottom. I reloaded software and restored from Time Machine, it now happens frequently. Any insight?

I have a late 2006 iMac that has just started giving me a message to reboot after a black screen comes down slowly from the top top of the screen to the bottom. I reloaded software and restored from Time Machine, but it keeps happening, now several tomes a day. Any insight as to the issue or a proposed solution?

Unplug any peripherals you have except your keyboard, reboot, and check activity monitor for apps. Keep running apps to a minimum to find the App causing the issue.

My Logitech bluetooth laser travel mouse does not connect at startup to my recently upgraded iMac. Even when this is configured. I need to configure the mouse everytime after startup!!

My Logitech bluetooth laser travel mouse does not connect at startup to my recently upgraded iMac. Even when this is configured. I need to configure the mouse everytime after startup!!... It worked fine with previous OS X .... How can I fix this??

My Logitech bluetooth laser travel mouse does not connect at startup to my recently upgraded iMac. Even when this is configured. I need to configure the mouse everytime after startup!!... It worked fine with previous OS X .... How can I fix this??

IMac 24" OS X 10.5.8 crashes after startup

After startup, my iMac crashes after a short while (from 10 seconds up to 10 minutes). The screen freezes and the keyboard doesn't respond. I can't click, however, i can move the cursor around. This iMac was bought 2008 and I've never had any problems like this before, and I have no idea what made it behave this way. (I noticed it had crashed when I tried to wake it up from sleep mode a couple of days ago.)
Things I tried that didn't fix the problem:
1. Shutting down and disconnecting power cord for 30 seconds
2. Reseting PRAM
3. Created a new login-account
4. Repaired disc permissions in Disc Utilities
5. Hardware test (holding "d" during startup)
(OBS. I've tried the extended hardware test several times but sooner or later it crashes, always before the test is finished!)
In Safe Mode (holding "shift" during startup) though, it doesn't crash, but then I can't have sound etc.
What kind of problem could this be? What should I do?

You mentioned running Apple Hardware Test however I'm guessing you may not have run in Extended Mode. If you did not then you really haven't tested it. When you start AHT look for Extended Mode and follow the instructions. This test will take significantly longer to do. My guess is you have temp sensor or HD problem.
Another thing you can do is run Activity Monitor when operating normally and look to see if you have any processes that are using a lot of %CPU, if you do that's a sign you have a problem process. You can also look for how much FREE RAM you have (it's under the System Memory tab) however being low on RAM would not cause a crash it would cause a slowdown.

Imac g5 repeated reboots after startup

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