IMac won't turn on after power cut

When my iMac is unexpectedly turned off, ether at the wall or during a power cut, it won't then come back on immediately. Sometimes it will come back on after an hour, sometimes after a couple of days. Anyone know why this is? There is no logic to it. I've tried all the trouble shooting stuff; the resetting SMC for example. And I've got a surge protector. I've also taken it into an Apple store, a round trip of 3 hours, twice already over the past couple of months. But after doing some diagnostic tests on it they can find nothing wrong. Also, when they go to turn it on, it fires up immediately. I was told that unless they experience the problem themselves they can't do anything. Which means I'm forever taking it in to them, during this problem, on the off chance it may still be a problem when I get there. It's very infuriating. Help!!!

Great advice. And I'll definitely do that - need to get my Mac back on and working before that however.

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IMac won't boot anymore after power cut

Thanks to the great storms in New Jersey, my iMac does not boot anymore after a power cut. Does not get past the apple logo screen with the spinning wheel and keeps rebooting every 2 minutes.
I was able to mount the HD via Firewire on a host machine and the disk seemed fine.
I booted from the Install disk and ran Disk Utility - seemed fine though I could not verify the disk permissions ?
One other thing - I seemed to remember the white light (front bottom right) was blinking before during start-up. Now it goes and stays black after couple of seconds.
Help please,
Philippe

HI Phillipe and Welcome to Apple Discussions...
If you haven't done so, try running the Apple Hardware Test.
http://support.apple.com/kb/HT1509
I doubt repairing disk permissions can't help this problem. It sounds like a hardware issue.
*"I booted from the Install disk and ran Disk Utility - seemed fine though I could not verify the disk permissions ?"*
When you ran Disk Utility via Firewire, did you actually Verify the hard disk for errors?
Carolyn

My iMac won't turn on after power flickered on and off.Is there a virus affecting it or is something ele wrong?

My iMac was on and we had our power flicker because of weather conditions. I know the computer is hooked up right because it was on before the power went out.So my question is, is there a virus that had been affecting it before it went off, or is the power button broken? And any help would be appreciated because we have just taken in other computers for various reasons and we really don't want to take it in again.Oh, and i don't really know which model it is. Thanks

Try an SMC reset - sometimes works:
SMC Reset
Shut down the computer.
Unplug the computer’s power cord and disconnect peripherals (printers/external hard disks, etc. but not keyboard or mouse).
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.

IMac 2ghz won't turn on after power loss

I really hope someone can help me. My 07 or 08 2 ghz iMac will not turn on after losing power which includes being unplugged or the power being turned off. This happens whether or not it is shut down properly. Once it will not turn on it must be unplugged and sit for about 12 hours or be plugged into a different outlet. Outlets are all fine. Have reset pram and all that stuff. It is surge protected. Any suggestions? Thanks

I have been having exactly the same problem as Mhuntet11.
My 2010 i3 iMac will not turn on after losing power, which includes being unplugged or the power being turned off.
It has happened to me 4 times now. In each case - nothing will get it started. But on each occasion - about 2 days after the power cut - the iMac will start up again, good as new.
I have also experienced the other thing that Mhuntet11 said:
"when it won't turn on I plug it into a different outlet and if it does turn on I can unplug it and put it back in the original outlet and it works fine"
Yep - once, after 2 days of trying every power point in the house, I finally started up in the kitchen. Not very practical, so I bit the bullet and powered it down again and moved it back to the office. It stared fine.
Does this sound like a fault that should be serviced? Or is there some re-set technique I do not know about.
I have followed the SMC reset procedure and it does nothing

Imac won't turn on after anti virus software downloaded

The Avast antivirus software was downloaded onto my imac and now my imac won't turn on. What should I do?

Troubleshooting: My computer won't turn on
Read and follow all the steps.
If you find yourself at Step 6 determine if you can start the Mac in "Safe Mode":
Safe Mode or "Safe Boot" is a troubleshooting mode that bypasses all third party system extensions and loads only required system components. Read about it: Starting up in Safe Mode
You must disable FileVault before you can start your Mac in Safe Mode.
Starting your Mac in Safe Mode will take longer than usual, graphics will not render smoothly, audio is disabled on some Macs, and some programs (iTunes for example) may not work at all.
Merely starting your Mac in Safe Mode is not intended to resolve the problem, it's to observe its performance without certain additional components.
To end Safe Mode restart your Mac normally. Shutdown will take longer as well.
Remove the Avast garbage by using its uninstaller. Never install it, or anything like it, ever again.

2008 iMac won't turn on after Mountain Lion installation

I have a 2008 iMac with 6GB of RAM that was running on OS X 10.6.8 perfectly. Tonight I upgraded it to Mountain Lion. After the installation, my machine was running slower and a little choppy, especially when first opening programs, even though it meets all the requirements for Mountain Lion. After about an hour or two of running like this, I was standing away from the computer for a minute when I saw a flash come from the monitor. I went to it and the screen was black. I thought maybe it had went to sleep, but nope! It was completely off and would not turn back on. No lights or sounds come on at all. There was no power outage or anything, and all other devices plugged into the same surge protector were working fine. I tried plugging it into another outlet and still had no luck.
Any insight onto what caused this? Is it most likely a power supply failure, and could this have been caused by the Mountain Lion installation? Considering I've had this computer for almost 5 years and this has never happened before, it seems obvious that this contributed somehow.
Any advice would be appreciated. I'm going to try to take it to an Apple store soon, but the earliest appointment is a few days away.
Thank you!

Welcome to Apple Support Communities
It's quite possible that the power supply failed. The failure is difficult to be related with OS X Mountain Lion, so I would discard that. In some cases, it's normal that you experience slowness after installing a new OS X version because Spotlight indexes the hard drive.
The best you can do is to take it to an Apple Store or reseller so you can get your Mac diagnosed. Now we can't do anything else apart from thinking that is a power supply issue

Old imac won't turn on after a week of inactivity

Hello,
I'm aware this question was answered elsewhere on this forum but the issue there seemed to be that the imac had been moved and/or jolted. In my case, I went to New York for a week and when I came home the imac just wouldn't turn on. I've bought a new power cable, checked all the connections, disconnected peripherals, tried command/control/power etc. Nothing. I've even tried starting from a Norton utilities disk.
There were no date/time issues the last time I used it but is it possible this could be a battery problem? Any thoughts why it might have just stopped after a week of not using it? (I normally have the computer on every day).
Please help!
Thanks,
KH
Imac G3 Mac OS 9.0.x Slot loading CD, Bondi blue

Hi dancebaby,
Thanks for visiting Apple Support Communities.
Start with these troubleshooting steps if your iPhone does not turn on:
iPhone: Hardware troubleshooting
http://support.apple.com/kb/TS2802
Will not turn on, will not turn on unless connected to power, or unexpected power off
Verify that the Sleep/Wake button functions. If it does not function, inspect it for signs of damage. If the button is damaged or is not functioning when pressed, seek service.
Check if a Liquid Contact Indicator (LCI) is activated or there are signs of corrosion. Learn about LCIs and corrosion.
Connect the iPhone to the iPhone's USB power adapter and let it charge for at least ten minutes.
After at least 30 minutes, if:
The home screen appears: The iPhone should be working. Update to the latest version of iOS if necessary. Continue charging it until it is completely charged and you see this battery icon in the upper-right corner of the screen . Then unplug the phone from power. If it immediately turns off, seek service.
The low-battery image appears, even after the phone has charged for at least 20 minutes: See "iPhone displays the low-battery image and is unresponsive" symptom in this article.
Something other than the Home screen or Low Battery image appears, continue with this article for further troubleshooting steps.
If the iPhone did not turn on, reset it while connected to the iPhone USB power adapter.
If the display turns on, go to step 4.
If the display remains black, go to next step.
Connect the iPhone to a computer and open iTunes. If iTunes recognizes the iPhone and indicates that it is in recovery mode, attempt to restore the iPhone. If the iPhone doesn't appear in iTunes or if you have difficulties in restoring the iPhone, see this article for further assistance.
If restoring the iPhone resolved the issue, go to step 4. If restoring the iPhone did not solve the issue, seek service.
Best,
Jeremy

IMac won't turn on after resetting SMC

Recently my 2011 iMac starts uttering strange noise even if the fan speed is low so I decided to reset SMC this morning. However, after unplugging for 15 sec and plug again. it just won't start! No matter how I pressed the power button, there is no reaction coming from my iMac. I tried to long press for 10 more seconds, re-unplug and plug in, and tried another socket on the wall but in vain. Do you have other ideas 'cause I have not backup my data and hope to grab something output before sending it to the APPLE store. Thanks.

If you get no video or audio at all and you have confirmed it's not the power source or power cord then that indicates your power supply may have failed.

IMac won't turn on after scheduled shut down

Hi, hope someone here can help me!
I have a 20" 2006 iMac. While it was still under warranty, it repeatedly froze, and eventually when I turned it on the screen remained blank although I could hear that the hard drive was at least trying to get started. I got it repaired (new logic board, new screen), but now I am having some of the other difficulties mentioned here, where the screen freezes when using graphic intense software, including 3D games. Sometimes, it works fine for hours, others less than 2 minutes. I used to keep it on all the time, with energy saver set to go to sleep when possible. I've found, though that the graphics problems are less likely to happen if it has been off at least overnight, so I set up the schedule for it to turn itself off in the small hours. The problem is, when I go to turn it back on, it won't come on unless i pull out the power cable from the back of it and put it back in again. Any ideas what's causing this? And any ideas on what I can do to fix it?
Thanks

This just happened to me today. Not sure what to do as yours was the only discussion like this.
Please let me know if you were able to restore it and how?
Extremely frustrated since it was brand spankin new!!

IMAC won't turn on after installing Magic Mouse

Hello
I Have an intel 2 core duo aluminum. I installed the magic mouse and now I cannot star it. I get the Grey screen, Some time with the apple, some times just the gray screen. When I load the installer disk and run disk utility, the hard drive does not show up. Any Idea on how to fix my problem?
Thank you
Raoul

I'm afraid so. Still. I wonder how it just happened the exact moment I installed the magic Mouse. Thought it could be a compatibility issue
Thanks anyway
Raoul

IMac 5K won't turn on after 3 weeks.

I have used only for 3 weeks.
Suddenly, iMac screen turned to black.
There are no clue of turn on.
I brought it to apple store on 4/16 and it is still in repair.
About 1 week ago, they were waiting for logic board and on Tuesday I got an call saying they will receive it shortly and still in process.
I used 3 weeks and I am waiting more than 3 weeks to get the product and be repaired.
Does any one have similar issue? How long does apple store normal take for repair iMac?
Am I just bad luck?

I have been having exactly the same problem as Mhuntet11.
My 2010 i3 iMac will not turn on after losing power, which includes being unplugged or the power being turned off.
It has happened to me 4 times now. In each case - nothing will get it started. But on each occasion - about 2 days after the power cut - the iMac will start up again, good as new.
I have also experienced the other thing that Mhuntet11 said:
"when it won't turn on I plug it into a different outlet and if it does turn on I can unplug it and put it back in the original outlet and it works fine"
Yep - once, after 2 days of trying every power point in the house, I finally started up in the kitchen. Not very practical, so I bit the bullet and powered it down again and moved it back to the office. It stared fine.
Does this sound like a fault that should be serviced? Or is there some re-set technique I do not know about.
I have followed the SMC reset procedure and it does nothing

My IMAC seems to have died after power surge. It shut down and won't start. What shall I do?

my IMAC seems to have died after power surge. It shut down and won't start. What shall I do?

I would recommend you try an SMC reset at this point:
Resetting the System Management Controller (SMC)
Resetting the SMC for Mac Pro, Intel-based iMac, Intel-based Mac mini, or Intel-based Xserve
Shut down the computer.
Unplug the computer's power cord.
Wait fifteen seconds.
Attach the computer's power cord.
Wait five seconds, then press the power button to turn on the computer.
If that fails to solve it, it is probable that the power surge damaged some of your iMac's hardware components, and will need to be repaired at an Apple Authorized Service Center.

I'm trying to set up a dual monitor for my new iMac. I'm using a second display I used with my old G5. My iMac recognizes the second monitor but the monitor won't turn on. Power button doesn't do anything on the monitor itself.

I'm trying to set up a dual monitor for my new iMac. I'm using a second display I used with my old G5. My iMac recognizes the second monitor but the monitor won't turn on. Power button doesn't do anything on the monitor itself.

If it won't turn on then the monitor is dead (power supply?, video circuits?). Not worth repairing.
If you have a new iMac then it has thunderbolt. So exactly what is that monitor you are trying to connect? For TB you can connect a mini-displayport monitor. Probably (not 100% sure with TB) can use dvi or vga too if you have the appropriate adapter.

What to do now when my iPad won't turn on after I turn it off. It shows only the apple logo. I am sure it has above 70% charge as when I sync my iPad it shows necessary detail in iTunes. I have tried, HOME & POWER button, but did not work.

What to do now when my iPad won't turn on after I turn it off. It shows only the apple logo. I am sure it has above 70% charge as when I sync my iPad it shows necessary detail in iTunes. I have tried, HOME & POWER button, but did not work.

First try a Reset ( No Data will be Lost )
Press and hold the Sleep/Wake button and the Home button at the same time for at least Ten seconds... (But can take Longer)... until the Apple logo appears. Release the Buttons
If no joy... Try a Restore...
1: Connect the device to Your computer and open iTunes.
2: If the device appears in iTunes, select and click Restore on the Summary pane.
Restoring > http://support.apple.com/kb/HT1414
Make sure you have the Current Version of iTunes Installed on your computer
iTunes free download from www.itunes.com/download
3: If Unable to Restore, try using the Steps in this article to force the device into Recovery Mode.
Note on Recovery Mode.
You may need to try this More than Once... Be sure to Follow ALL the Steps...
After you have Recovered your Device...
Re-Sync your Content or Restore from the most Recent Backup...
Restore from Backup > http://support.apple.com/kb/ht1766

My Apple TV won't turn on after a problem with the power bar. I've unplugged both cords and left an hour before plugging back in. Any suggestions?

Apple TV doesn't turn on after power glitch. Unplugged both cords, left an hour, and plugged back in with no success. Suggestions?

check out this discussion.
you should definitely get a decent UPS to protect your investment.
something like the APC Back-UPS ES 700 should suffice.

IMac won't turn on after power cut

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