Imac wont start up after power failure

i moved the table my imac was on and i accidentally took off the power cable.the imac was on so when i took the cable off it shut off. then i put the cable back and tried to turn it on but nothing happened..it is like dead. any suggestions?

Also, there is a small battery or capacitor on the logic board that may need to be replaced, as this has been the cause of a similar issue over many generations of Mac computer hardware. Of course there are other causes of failure, and that is why the help of an expert to troubleshoot and diagnose issues to attempt to resolve them can take time.
And it may not be resolved after the first attempt if the actual problem is deeper than first best educated guess arrived by troubleshooting. Part of some repairs requires replacement of suspect parts, even if they may not be the cause, to eliminate their being within the realm of possibility. A good read is among the original Apple Technical Service Manuals, those aren't often available to the general public. I used one to self-troublehoot an iMac under AppleCare after the nearby 200+ miles one-way distant 'specialist' could not fix my new iMac, four times. So I am a bit cool on newer Macs; the way I see it one new headache lasting 10 months and requiring 3,000 miles travel, to not be resolved by experts (and under warranty, so I can't touch it!?!) is enough.
The best cure for main power failure, is to have a good high quality battery backup system in place with automatic voltage regulation, that also works as a power filter; and can step in to isolate the Mac from mains high-or-low power fluctuation. This can save many products from bad power sources; do not rely on these, either. Make copies of your work ahead of time. This saves your computer from issues you can prevent.
PS: my Macs seldom are shut off, for up to 11 months, some of mine only get to sleep when not in use. When the main power goes offline, during a storm or extended utility failure of their own making, I will have to shut them off as a choice. There is software in the UPS unit that can help shut down automatically, and that is a choice, too. I usually find their software problematic on occasion; and the battery backup is not very long in duration, so one with a few hours runtime and a method of rationing the power if you are present when the mains fail, is helpful in performing a normal shutdown after a power failure.
Good luck & happy computing!

Similar Messages

  • IMac wont start up after power shortage

    Hi !
    yesterday I had a sudden power outage in my apartment while my iMac (September 2010) was running. Now it won´t start when I press the power button. Any suggestions?

    Zap the PRAM and Reset the SMC, then try again.
    If no go, contact Apple Service, iMac Service or Apple's Express Lane. Do note that if you have AppleCare's protection plan and you're within 50 miles (80 KM) of an Apple repair station, you're eligible for onsite repair since yours is a desktop machine.

  • IMac won't boot after power failure?

    My iMac wont boot or respond in any way after I experienced a brief power outage. Now it can't seem to switch on at all even after attempting the different resets I've read on other discussions. Please help with advice on any techniques to fix it otherwise steps I must take to get it repaired. Thanks.

    Hello, not much you can do other than try this...
    Intel-based Macs: Resetting the System Management Controller (SMC)...
    http://support.apple.com/kb/HT3964

  • Can't start up after power failure.

    Greetings.
    Here in the Santa Cruz mountains we experience occasional power outages. After an outage, when I attempt to re-start the computer, it doesn't get past the spinning spokes (or whatever you call that thing). The thing just keeps spinning until I press the power button, shut the computer off, and re-start. After one or two tries, it starts up, but I'd like to know how to prevent the problem in the first place.
    G4 Dual 450   Mac OS X (10.3.9)   1 GB RAM

    The first thing you should do after an abnormal shutdown is boot from your OS X Installer Disc and use Disk Utility to repair both the hard drive and permissions.
    There are two ways to prevent a problem like this:
    1. Buy an external Firewire drive and backup software. Maintain a bootable backup of your system on the external drive. Update incrementally on a regular schedule - Daily for your work files; weekly for the entire system.
    2. Buy an Uninterruptible Power Supply (UPS) with sufficient capacity to keep your system running long enough for you to shutdown normally until power is restored. Usually this means a UPS with enough capacity for about 10 minutes of operating time on battery. Of course you can buy as much capacity as you are willing to spend money for if you want longer operating times during blackouts.

  • IMac not booting up after power failure

    work around for at home/personal users which should work, the OS try's to retrieve user authentication Info from the previous logged on user so disconnecting the network cable or disabling or turning off the WiFi/ wireless should do the trick, just make sure the power is fully drained or have the power cable or battery disconnected for 25-30seconds to ensure the power is drained from the system. For all those Domain Admins/Users enable do not write on the users directory so the OS doesn't recognize a user account to try and retrieve info, if you perform this the OS will just create a temp user profile folder and delete it when theirs a power failure and not try to look for it after the power failure when booting up not causing to give you the gray boot up splash screen and go right into OS X, hope this helps and good luck!

    work around for at home/personal users which should work, the OS try's to retrieve user authentication Info from the previous logged on user so disconnecting the network cable or disabling or turning off the WiFi/ wireless should do the trick, just make sure the power is fully drained or have the power cable or battery disconnected for 25-30seconds to ensure the power is drained from the system. For all those Domain Admins/Users enable do not write on the users directory so the OS doesn't recognize a user account to try and retrieve info, if you perform this the OS will just create a temp user profile folder and delete it when theirs a power failure and not try to look for it after the power failure when booting up not causing to give you the gray boot up splash screen and go right into OS X, hope this helps and good luck!

  • IMac wont start up after upgrade to Mavericks

    I installed Mavericks as an upgrade to OS X 10.6.8 on my iMac and with in a half an hour of use my computer froze, I have tried all the normal rebooting techniques but my opening screen still has the vertical green stripes, even after using the disk repair/first aid utility, the iMac freezes without fully booting. the disk repair found no issues and says all is OK.

    Hello Tone56,
    It sounds like you are unable to successfully boot your computer after upgrading to Mavericks, and are seeing some graphical anomolies on startup. I recommend starting by resetting your PRAM with this article:
    OS X Mavericks: Reset your computer’s PRAM
    http://support.apple.com/kb/ph14222
    Note: To print these instructions, open Help Viewer’s Action pop-up menu (looks like a gear), then choose Print.
    Shut down your Mac.
    Locate the following keys on the keyboard: Option, Command (⌘), P, and R. You will need to hold these keys down simultaneously in step 4.
    Turn on your Mac.
    Immediately press and hold the Option-Command-P-R keys. You must press this key combination before the gray screen appears.Continue holding the keys down until your Mac restarts, and you hear the startup sound for the second time.
    Release the keys.
    Resetting PRAM may change some system settings and preferences. Use System Preferences to restore your settings.
    Then reset your SMC:
    Intel-based Macs: Resetting the System Management Controller (SMC)
    http://support.apple.com/kb/ht3964
    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 the issue persists, try performing a Safe Boot then restart as normal to see if that will allow you to boot normally:
    OS X: What is Safe Boot, Safe Mode?
    http://support.apple.com/kb/ht1564
    Starting up in Safe Mode
    To start up into Safe Mode (to Safe Boot), follow these steps.
    Be sure your Mac is shut down.
    Press the power button.
    Immediately after you hear the startup tone, hold the Shift key.
    The Shift key should be held as soon as possible after the startup tone, but not before the tone.
    Release the Shift key when you see the gray Apple logo and the progress indicator (looks like a spinning gear).
    After the logo appears, you should see a progress bar during startup. This indicates that your computer is performing a directory check as part of Safe Mode.
    To leave Safe Mode, restart your computer without holding any keys during startup.
    Thank you for using Apple Support Communities.
    Cheers,
    Sterling

  • Problems With Starting Up After Power Failure

    Hi Everyone,
    I'm having the strangest problem booting up (or rather, not being able to boot up) after a power outage in my neighborhood last night. What's more, it's the second night in a row that it's happened and has blocked my ability to boot into my two main drives. I installed OSX on a separate internal drive so that I can access them and they seem to be all right and have all the information on them which is good.
    Here's what happened: Two nights ago my computer was on and we had a power outage which turned my computer off, of course. I don't have it set to restart after something like this so I tried to restart it in the morning. The blue progress bar makes it about a quarter of the way across and stops. I have the same OS on another drive so I started up with the Option key and chose that and everything was fine. However, the next night the exact same thing happened and I couldn't boot into that drive the following morning either so I had to install a fresh version of OSX on another drive just to get into my computer. I've used Drive Utility, Drive Warrior, Drive Genius and TechTool Deluxe to check the drives and they all say there's nothing wrong. I've tried to reset the PRAM but still can't boot up into those drives which were on when we had the outage. I have unplugged everything and nothing else in the house seems to be effected. Any suggestions? I've had many power outages over the years with my Mac on but never have I ever experienced something like this, and on both drives too! As always, any help will be greatly appreciated and needless to say, I'm turning my computer off tonight before I go to bed!

    Sounds like a lesson in there: don't wait to put OS X on an external drive that is usually off line.
    Rush to a store or on-line and get a UPS of the 1500VA sort (APC RS would be nice, or SMART UPS 1000VA).
    The directory of the drives could be corrupt.
    I have all my equipment, modem, routers, the works, but we had a bad storm and one port on the router/modem is out (the one I used, the modem seems to be okay) and I am worried that the UPS's line filter for DSL in is also 'compromised.'
    Storms and power outages can wRECK or cuase havoc.
    It sounds like you need to map out bad sectors maybe (zero all in Disk Utility) perhaps. The directory, volume blocks, or even journal file, got scrambled. However, because no test can find it means - to me - it could be the "non user partitions" rather than OS X partition etc. Hence, zero the drive or just reformat it in full.
    Why have you not ever with these outages, just continued to live w/o one? I wouldn't just shutdown, I would unplug if a storm approaches.
    PS: SMC Reset button is under drive bay #4. Give it a 5-10 seconds depress.

  • Imac wont start up after new RAM, no chime, black screen

    Hi, I've recently purchased a used 2010 iMac i3 that had faulty RAM.
    This was confirmed as the issue when I tested a friend's original RAM from the same age iMac and the machine worked perfectly.
    I then ordered 2x 4gb Crucial memory (upgrade from the 2x 2gb already installed) but kept getting kernal errors and RAM integrity check errors so the modules were returned and replaced by crucial.
    Prior to returning, I attempted to reinstall a fresh copy of mavericks, but the hard drive failed to completely format, and then the OS install also failed so the machine currently now has no operating system. However before returning the ram the machine would boot up and connect to the internet to attempt to download the OS again.
    The replacements have now arrived, but after installing the machine won't even boot. First attempt to start there is a drive noise, and the fans run, but no chime and a black screen. If I force shutdown and try again the drive noise happens twice and the fans run, but the same outcome.
    If I remove the RAM I still get the single bleep, and once of all of the times I've removed and reseated the RAM I've had a triple beep integrity check fail.
    Any help would be massively appreciated. Lost now as to whether the issue is with crucials RAM or the iMac itself.
    Thanks

    Do you still have the old ram? Was orig sticks of ram bad? What happens if you put only one stick of the orig ram back in ?

  • IMac won't boot after power failure during 10.5.6 update

    Help!
    Tried to update last night and at something like 80% install, we had a power cut. iMac won't boot at all now - get to a grey screen which tells me to restart. Don't have a wired keyboard. If I did - what are the steps to get this working again.
    I believe I have a good backup, but don't want to risk as all the family photos are on the iMac.
    Thanks in advance.

    Thanks for the help, but can't even get to a screen where I could type anything! I know I'm being dumb here.

  • Controled Auto Start DomU after power failure

    Hi, all,
    I was hoping to get a few pointers on this. I have a 2 DomU "nodes" for a demo Oracle Apps Vision. My server (basic rack mount PC) is hooked up to a UPS battery backup. I managed to install NUT on the Dom0 (usb to the battery) and DomU (network to Dom0). When the battery goes critical, the DomUs shutdown, then the Dom0 shuts down. So far, so good.
    Now, when the server restarts (wol from the router for now), I was hoping to restart my DomUs in a controlled manner (meaning start my db node first, then my Apps server node a bit later) without manually going to the web interface. I guess I can do this with Xen directly (xm create or links in /etc/xen/auto), but is this going to confuse the VM Manager and possibly leave the VM database out of sync? Is there a Python script I should use instead? Thanks for sharing your thoughts.

    user12262982 wrote:
    Now, when the server restarts (wol from the router for now), I was hoping to restart my DomUs in a controlled manner (meaning start my db node first, then my Apps server node a bit later) without manually going to the web interface. I guess I can do this with Xen directly (xm create or links in /etc/xen/auto), but is this going to confuse the VM Manager and possibly leave the VM database out of sync? Is there a Python script I should use instead? Thanks for sharing your thoughts.You can use both xm and the */etc/xen/auto* symlink method: VM Manager periodically polls the pool and will automatically detect that the guests have been started. You could also use the HA functionality within Oracle VM itself to automatically start the guests, but I'm not sure you could do that in a controlled fashion, i.e. the startup process would be non-deterministic.

  • I have a iMac that wont start up after it sits for a short time

    I have a iMac that wont start up after it sits for a short time. I changed out the hard drive and reinstalled Leopard. If I mess with it a little I can get it to start up usually by repairing the hard drive with another computer, one time I just held down the P-R-option and command keys and it worked. Once its on it will restart no problem but if it sits for and hour or so it will get stuck either in the grey screen or blue screen. I also pushed the smu button but didnt work. Please help? Thank you.

    For this type of question, we need to know which iMac you have. This forum covers G3, G4, and G5 iMacs that have different hardware, and any recommendations are better handled if people know which you have. For starters, do "About this Mac" from your Apple menu and look at teh processor type.
    You also need to tell us the version of the Mac OS you have, also avaiabe from "About this Mac.
    If the processor type says "Intel," you have a newer iMac that this forum covers and should report in the area for current iMacs here:
    iMac (Intel)

  • Intel imac wont start after changing permission

    intel imac wont start after i changed my hard drive permission to let me read and write, then i clicked apply to all enclosed files.i turned it off no problem. then it never started up again in os x. the grey screen with apple logo appears,then after a minute it restarts, and will keep doing that if i let it. i can start up in windows xp, but i dont know how to do anything in windows xp that will affect os x. i can use the hard drive in target mode, but i cant figure out how that can help me. i use a macbook to view target disk. ive spent hours looking through help and support. finally i do not have the os install disks. PLEASE HELP!

    My apologies for the inept instructions.
    Restart normally. Open Terminal in the Utilities folder. Paste the commands in the Terminal application to avoid typos:
    sudo su
    Press RETURN. Enter your admin password when prompted.  It will not be echoed to the screen. Press RETURN again. Now paste each of the following at the prompt and press RETURN after each.
    chown root:admin /Applications
    chmod 0775 /Applications
    chown root:admin /Library
    chmod 1775 /Library
    chown root:admin /System
    chmod 0775 /System
    chown root:admin /Users
    chmod 0775 /Users
    chmod -R -N /Applications
    chown -R :admin /Applications/*
    Again, my apologies.

  • Trouble booting up after power failure

    After power failure(two hours), when booting up imac, just get a grey screen with blinking folder icon containing question mark.
    I can hear clicking noise (hard drive?) that goes two or three clicks and then seems to give up.
    How do I get it rebooted. Have disconnected and tried again with no result.

    Sounds like the power failure may have fatally damaged the HD. Going forward use a UPS to protect your system, power surges can be very damaging to computers. You and try troubleshooting using Apple's Flashing question mark appears when you start your Mac but I think you may find the HD has failed. For confirmation you cal also run Apple Hardware Test in extended mode. Run AHT about 3x back to back and if it reports errors it's time to take the machine in for service.

  • Domain controller VMs using dynamic VHDx corrupt after power failure

    Over the past couple of months I have experienced 4 dead 2008 R2 SP1 domain controllers after power failure on Hyper-V 2012 hosts. The domain controller VMs will start after power failure and have varying degrees of file system corruption. In each instance
    the corruption has rendered the domain controller unusable. The problem has not occurred with every power failure, but in testing the failure rate has been over 10%.
    The Hyper-v 2012 hosts are as follows:
    Dell PowerEdge r720 with flash backed write cache on Raid controller
    Dell PowerEdge T710 with battery backed write cache on Raid controller
    Dell PowerEdge T310 with a single SATA hard drive and write cache disabled
    Generic system with a single SATA hard drive and write cache disabled
    The VM configuration experiencing corruption is as follows:
    Each VM was created from a base 2008 R2 SP1 syspreped VHDx image template file (40 Gigs)
    The image template was originally created as a VHD and was then converted to a VHDx
    The VHDx file has 512k sectors instead of the native 512e of VHDx files (a result of VHD - VHDx conversion)
    Each VM was assigned 1024 Meg RAM and 1 virtual processor
    The domain controllers were created by promoting the base 2008 r2 install to a DC after base image deployment
    Only one corrupt VM was not running the 2012 integration components. The rest were running current 2012 integration components
    I have done extensive testing on this issue and the problem for me seems to revolve around the VHDx file format. I have managed numerous Hyper-v installations since the original 2008 server version was released and I have never seen corruption like this
    until 2012 and VHDx.
    For the past few days I have been testing fixed sized VHD VMs on a 2012 host and I have not been able to reproduce the data corruption issue. I seem to only be able to reproduce the problem when using dynamic VHDx files. I have not done any testing on 2012
    hosts with fixed size VHDx files or dynamic VHD files.
    It would be great to hear from anybody else experiencing similar issues so that we can compare notes and hopefully get to the bottom of this problem.

    To be honest I was excited to see this fix released, but there are two problems.
    1. The hotfix causes BSOD if you have VLANs with a teamed NIC configuration. I found this out the hard way on a production system. How in the world did this thing get through testing and into automatic updates?
    2. The hotfix does not seem to resolve the issue in my test environment.
    I opened up a case with support and they informed me that they would not provide support for this issue and that I had to open a case with premier support. Premier support informed me that I cannot open a case with them unless I sign a $50,000 per year service
    contract. Is there anywhere to get support on this issue?

  • Reset TC with Original Settings after Power Failure

    TC blinks yellow after power failure. How can I reset to original (before power failure) network settings?

    Here you go: How to reset Time Capsule

Maybe you are looking for