IMAC fails to boot up

My IMAC fails to boot up. The IMAC powers up, the white backround with the Apple and the windmill spins completes, the system goes to the blue screen, and then a overlay fills the screen with a power button image in gray appears in the center of the monitor with text overlay in several languages instructing me to restart the computer. When I do this the same thing occurs. Can you help.

I believe you are experiencing a "Kernel Panic"....this link will explain what it is and hopefully how to resolve it
http://www.thexlab.com/faqs/kernelpanics.html

Similar Messages

IMac fails to boot from DVD

I want to repair my HD, but my iMac fails to boot from either the Leopard install DVD or the original install CD for OS X. What can I do?

Gary:
Thanks for your reply. How and what with both installers: I hold down the "C" key until the Apple logo appears. The only thing that happenshat happens is that the little "sunball" spins interminably. I waited at least 10 minutes before deciding that it was hopeless.
I hear ya regarding the external HD but unfortunately don't have one. Mario

Imac fails to boot - at all

Hi,
I restored my imac using original disks and then updated the osx to current over the web. all fine so far. then restored the system (full disk image) from time machine to recover my data. restore said it worked ok but when the machine restarted it failed to boot and i just get a list of script top left of screen saying launch faild, debugger called etc. Then gray screen and grey box in middle of screen saying you need to restart the computer. This i have done numerous times but it just does the same thing again and again. More worrying is that the machine will not boot from original disks either. Any ideas before I take it to the apple store?
Thanks, Pedro

If the disk image or time machine backup was from a older version of OS X then what was currently installed restoring that image/TM backup may have corrupted the newer version of OS X.
I suggest you start over by wiping the drive completely, then Restore your Mac from that TM/Image backup and Then Upgrade to Mavericks.
You have the steps slightly backwards. The latest thing you should do is upgrade the OS to the newest version.

IMac fails to boot after restart. Shows folder icon with ?

I have managead to boot up from start up disc previously. I did a hardward scan and it stated my hardware was fine. It is my understanding the folder icon with the "?" means that the iMac can't find the OS. I thought maybe I had a corrupted spot on my HD where the OS is, and tried to re-install, and I wasn't allowed to re-install. Do you think my HD is bad, or maybe I have a virus? I'm ashamed to admit that my anti-virus software had been expired for a bit. I should also mention I am running OSX Tiger. I know, bad Apple geek, but it more than served my needs. This is last ditched effort before I take it in for service.

Highly unlikely it's a virus.
The question mark on startup can mean several things. One the hard drive is failing or failed or your Mac cannot locate a System Folder to boot from.
Try starting up while holding down the Option key. If there's a volume to boot from you'll see the Startup Manager window where you can select the startup disk to restart from.
A flashing question mark appears when you start your Mac
and tried to re-install, and I wasn't allowed to re-install.
Not a good sign.

My iMac fails to boot

My iMac (24", 3.06Ghz Core 2 Duo, 4GB, 500GB, 10.7.2) today froze on the screensaver. It wouldn't respond to any input so I held down the power button to turn it off.
When trying to turn the iMac back on, the screen stays blank. I can hear the fan come on, and "burst" slightly as normal when starting up. The SuperDrive clicks a few times and the hard drive clicks for a while but then nothing. After about 30 seconds, the SuperDrive clicks again and it repeats like that indefinitely.
I've tried the following troubleshooting steps:
Disconnect all peripherals
Hold down the Cmd+R to get into the Lion Recovery mode, but screen stays blank
Hold down the Option button to try to choose another boot device (including a Lion Recovery USB disk), but screen stays blank
Hold down the Option+Cmd+R+P to reset the PMU, but screen stays blank
DIsconnected the power, left for 15 seconds, reconnected. Waited for 5 seconds, turned on, but screen stays blank
Powered down, removed both memory chips and turned the iMac back on. The iMac complained about not having memory installed with the audible beeps, but screen stayed blank
Reinserted one stick of memory and tried turning the iMac on, screen stays blank
Inserted the other stick of memory in the same slot, same result
Inserted the stick into the other slot, same result.
Tried connecting to the iMac via Ethernet from a laptop, but the iMac does not come on the network.
I think I've run out of options! Unfortunately, my extended AppleCare ran out back in August, so I'd appreciate any advice to help me get back up and running!

Sorry to hear.
Seems that Apple call on Monday is ypur only choice then since you've already done everything else.
Good luck
Stefan

IMac fails to boot or mount as target in TDM

I recently attempted to install SL on my 2.4Ghz C2D iMac with 10.5.8. I inserted the disk, and clicked "Start Installation". It cranked along happily (albeit slowly -- started at 45 min to finish, then increasing as high as 58 min to finish) until the reboot. It went down and didn't come back up.
Now, when I start it up, the Apple comes up, it spins for awhile, and eventually just powers down. In verbose mode, there is an I/O error. I think the hard drive is fried.
However, I can't mount the computer in Target Disk Mode (TDM). I am able to mount the superdrive on my other computer, so I have a feeling that the Superdrive is set as Master on ATA0. I feel like my only choice is to take the drive out and try to recover data using it as an external. Any other ideas?
(My most recent backup is good, but I just uploaded some pictures and work documents that I would like to get. <10 MB to recover, thankfully.)

The recent iMacs use internal SATA connections (at least for the hard drive), so there should not be any master/slave setting involved. The hard drive should be accessible using FireWire Target Disk Mode.
You should insert the Snow Leopard installation disc and restart with the C key held down to force startup from the optical drive. When you get to the first Installer screen, go up to the menu bar and select to run Disk Utility from the Utilities menu. See if your hard drive appears in the sidebar.
If it appears there, is it just the drive, or is there a volume under the drive. Hopefully, there is a volume. Either way, select the drive and go to the +First Aid+ tab. Run +Repair Disk+ (not +Repair Disk Permissions+ ). Note if any errors are found, and if errors are found, note if they are repaired.
After it completes, quit Disk Utility and Installer and attempt to restart normally.
If errors are found but not repaired, you can try using a third party utility, such as DiskWarrior (Alsoft) or TechTool Pro (Micromat). If your backup is a clone, you can try cloning the clone back to the internal drive. If you backup is only your personal data, you can reformat (erase) the internal drive, install Snow Leopard on a blank volume, install your third-party apps, and restore your user data.
If you have an external drive (FireWire or USB) that can be used to for a system installation (so you can start up from it), or if your backup happens to be a bootable clone, please post back. You may be able to boot from it to recover any of the data that is not backed up.
Note: If Disk Utility found errors, it is likely that they existed before your Snow Leopard installation attempt, which is why the installation did not proceed normally.
Also, although you can start the Snow Leopard installation process while started up normally (unlike previous Mac OS X releases), I feel it is more reliable to start up from the Snow Leopard installation disc and run the installation from there.

IMac fails to boot

My 2007 iMac (10.5.6) has stopped working. When I try to turn it on it makes the sound then the screen goes white and an apple logo appears, and then the 'thinking swirl" goes below the logo, and it doesn't do anything else (it appears to be in a loop. What do I do to make it boot?

HI,
Boot from your install disk and run Disk Utility to check for errors.
Insert Installer disk and Restart, holding down the "C" key until grey Apple appears.
Go to Installer menu and launch Disk Utility.
Select your HDD (manufacturer ID) in the left panel.
Select First Aid in the Main panel.
*(Check S.M.A.R.T Status of HDD at the bottom of right panel. It should say: Verified)*
Click Repair Disk on the bottom right.
If DU reports disk does not need repairs quit DU and restart.
If DU reports errors Repair again and again until DU reports disk is repaired.
When you are finished with DU, from the Menu Bar, select Utilities/Startup Manager.
Select your start up disk and click Restart
While you have the Disk Utility window open, look at the bottom of the window. Where you see Capacity and Available. *Make sure there is always 10% to 15% free disk space*
If you cannot boot from your install disk, try booting in Safe Mode
What is Safe Mode
You could also try the Apple Hardware Test.
http://support.apple.com/kb/HT1543
Carolyn

My imac will not boot- it gets stuck on blue screen and will not go any further

Since the last update to Snow Leopard- My computer seems to perform fine, but when I restart the computer or shut it down and then turn it back on- it gets hung. SOmetimes I get the You need to restart screen. But, most times, it goes to the blue screen. The mouse shows up and the dissappears. It shows back up and the dissappears again. Then the system working spiral comes on and off every few seconds. But- it never gets to the sign in screen. ANyone know how to fix? What am I doing wrong?

Does your iMac fail to boot every time or only some of the time? Here are some things to try:
- Boot into "safe mode", which will run the equivalent of Disk Utility's "repair disk" operation.
- Boot from the system install disc that came with that Mac with the "D" key held down to run the diagnostics. Run them several times to see if any hardware problems are reported.
- If you can't identify the problem or fix it any other way, download and install the OS X 10.6.7 "combo" updater.
- If that still doesn't help, try reinstalling OS X 10.6 over the top of what's on the disk.

IMac won't boot OsX Partition after Bootcamp install/uninstall.

Hello,
I have bought 2 late 2012 21.5 iMacs last year and have used both the same way. Here is what happened with one of them recently.
Fisrt af all I've installed bootcamp 1 year ago in both iMacs without issues and was ok so far, and was using exclusively Windows 7 partition. The trouble iMac started with some startup issues during boot/reboot (screen was frozen with green/grey horizontal lines), but worked fine after following manual start up.
Lately I've been trying to boot from OsX partition and it freezes in the apple logo every time.
I have already done the SMC / PRAM procedures, without success.
I have tried to download and do a fresh OsX install (Mountain Lion, Mavericks and Yosemite). Can't boot from Mavericks / Yosemite flash drive install (both freeze at apple logo - horizontal lines), and only had partial success with one Mountain Lion 10.8.5 flash drive install that booted all right and the first part of the installation process was ok, but after the initial reboot, it happened to freeze the same way before.
The iMac failed to boot in safe mode (stops booting at 25% and then freezes on apple logo), and show no issues with AHT tests.
I can boot in single user mode, but it reboots after a few seconds. I noticed some errors messages during this boot.
It fails to boot in verbose mode, showing a few lines of errors (images attached), and then freezes in a green horizontal line screen.
I can still boot from Bootcamp flash drive and Ubuntu Flash drive, and install both OS. The only issue is with OsX itself. I have used Gparted in Ubuntu to Format the hole partition to HFS+, and can't find any errors in hard drive tests.
I thought about buying a thunderbolt cable and try to do a Clone of my other iMac, but don't know if it will work.
Any other tests/suggestions about this issue?
Regards,

Fixed the problem with this setup
Of course this means i just lost 4GB.
Let me tell the full story.
In the beginning, long ago, once upon a time. My iMac had 2x2GB ram sticks which were in the two DIMM1 Banks. I then told myself "I WANT MORE RAM BECAUSE LOLZ". So i bought 2x4GB ram sticks. The two empty slots were Bank 0/DIMM0 and Bank 1/DIMM 0. and I added them in there. having done that, I booted OS X up, worked great, had 12GB, everything was shiny and beautiful. Soon after I wanted to try it out on windows. I restarted my computer and BAM the blinking cursor just sits there, being stubborn and all. I then told myself "holy balls, this new ram i got is bonkers" (them words, I blame the language filter). Then after giving it a little thought, i just asked myself if it was because I had ram from two different manufacturers. I removed my old ram, which has nice Samsung stickers on them, and booted it up on windows. Still had the same problem, I then decided that maybe this is all really mentally challenged so to win I had to think like a retard. I took my new ram and inserted it in the same slots where my old ram sticks were (DIMM1 Banks), booted windows up and IT WORKED.
I still hold all of my WHYs on this subject but I will keep messing around to see if I find a better solution than just leaving both DIMM0 banks empty

Help need to Recover data from 2009 iMac failing drive won't boot?

How can I boot my 2009 iMac which came with Snow, from my macbook pro yosemite to recover my data on iMacs failed drive?

Yes in target mode can I do wirelessly? or does it need wired firewire cable between the computers?I want to try to repair from disc utility and recover my data using my data rescue app first.Will there be any problems using
macbook pro which is using
yosemite?

My Imac fails when I try to upgrade from Snow Leopard 10.6.8. I have to boot up from disk. Does anyone know how to overcome this problem?

My iMac fails when I try to upgrade from Snow Leopard 10.6.8. I have to boot up from disk. Does anyone know how to overcome this problem?   I need to upgrade in order to install latest software.

It would be lovely to know what your talking about. Upgrading from Snow Leopard does not involve discs.
Upgrading to Lion
If your computer does not meet the requirements to install Mavericks, it may still meet the requirements to install Lion.
You can purchase Lion at the Online Apple Store. The cost is $19.99 (as it was before) plus tax. It's a download. You will get an email containing a redemption code that you then use at the Mac App Store to download Lion. Save a copy of that installer to your Downloads folder because the installer deletes itself at the end of the installation.
     Lion System Requirements
       1. Mac computer with an Intel Core 2 Duo, Core i3, Core i5, Core i7,
           or Xeon processor
       2. 2GB of memory
       3. OS X v10.6.6 or later (v10.6.8 recommended)
       4. 7GB of available space
       5. Some features require an Apple ID; terms apply.
Upgrading to Mountain Lion
To upgrade to Mountain Lion you must have Snow Leopard 10.6.8 or Lion installed. Purchase a redemption code at the Online Apple Store: OS X Mountain Lion. Mountain Lion is $19.99 plus tax. Use the code to redeem a download of Mountain Lion from the App Store. The file is quite large, over 4 GBs, so allow some time to download. It would be preferable to use Ethernet because it is nearly four times faster than wireless.
     OS X Mountain Lion - System Requirements
       Macs that can be upgraded to OS X Mountain Lion
         1. iMac (Mid 2007 or newer) - Model Identifier 7,1 or later.
         2. MacBook (Late 2008 Aluminum, or Early 2009 or newer) - Model
             Identifier 5,1 or later.
         3. MacBook Pro (Mid/Late 2007 or newer) - Model Identifier 3,1 or later.
         4. MacBook Air (Late 2008 or newer) - Model Identifier 2,1 or later.
         5. Mac mini (Early 2009 or newer) - Model Identifier 3,1 or later.
         6. Mac Pro (Early 2008 or newer) - Model Identifier 3,1 or later.
         7. Xserve (Early 2009) - Model Identifier 3,1 or later.
To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right.
     Are my applications compatible?
         See App Compatibility Table - RoaringApps.
Upgrading to Yosemite
You can upgrade to Yosemite from Lion or directly from Snow Leopard. Yosemite can be downloaded from the Mac App Store for FREE.
Upgrading to Yosemite
To upgrade to Yosemite you must have Snow Leopard 10.6.8 or Lion installed. Download Yosemite from the App Store. Sign in using your Apple ID. Yosemite is free. The file is quite large, over 5 GBs, so allow some time to download. It would be preferable to use Ethernet because it is nearly four times faster than wireless.
    OS X Mavericks/Yosemite- System Requirements
    Macs that can be upgraded to OS X Yosemite
         1. iMac (Mid 2007 or newer) - Model Identifier 7,1 or later
         2. MacBook (Late 2008 Aluminum, or Early 2009 or newer) - Model Identifier 5,1 or later
         3. MacBook Pro (Mid/Late 2007 or newer) - Model Identifier 3,1 or later
         4. MacBook Air (Late 2008 or newer) - Model Identifier 2,1 or later
         5. Mac mini (Early 2009 or newer) - Model Identifier 3,1 or later
         6. Mac Pro (Early 2008 or newer) - Model Identifier 3,1 or later
         7. Xserve (Early 2009) - Model Identifier 3,1 or later
To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right.
     Are my applications compatible?
         See App Compatibility Table - RoaringApps.

IMac Model No: A1312 running OS X fails to boot.

I work in a school. We have a number of Mac devices. One being an iMac Model No: A1312 running OS X. Today this machine failed to boot – instead it started up but after about a minute of a screen with the Apple and the spinney cog wheel it dumped to a dark grey screen with an active cursor and responsive keys on the keyboard (the beep was heard when pressing the spacebar for example) but no log on box or other screen activity.
I have tried all sorts of diagnostics – hard drives comes up as ok. Reload of OS X – twice but always the same result.
Any suggestions as to what’s wrong please fellow Forum members?

Thanks for your lone response @rkaufmann87 I'd have thought more responses were offered - perhaps an indication that this is a rare issue.
There are no peripheral devices connected - the KB and mouse are wireless and clearly communicating with the device well. I've tried the suggested resolutions without the LAN cable connected and as stated in my OP with the LAN connected (from two different locations) can access the support pages etc. and indeed the machine has spent in excess of 4 hours powered up and twice reinstalling the OS X. All seems to go well but then after the restart up comes the standard start screen with the Apple Icon and the spinning cog wheel then after a minute or so it dumps out to a darker screen with just the mouse cursor visible. The mouse moves the cursor and pressing various keys on the KB brings beep responses.
As a School Network Manager, working with a very tight school budget, I'd rather get the machine sorted with Forum help and my in house effort if at all possible. The last iMac job I put out to a recommended Apple repair Workshop was for a replacement screen to a still under warranty new 21 inch iMac and that cost about half the value of the machine to get done - ouch!

Imac firmware, failed to boot

hello, i have a tray-loading imac and i installed 10.2 and forgot to install the firmware, now it failed to boot, what do i do? i tried to press the option button during start up and nothing happened, i also tried to safe boot, and zap the pram- now what do i do? i need to get this done quickly! Please help!

The Mac Guy 12,
Have you tried rebooting with everything disconnected (ethernet, printer, etc.)?
Any third party add-ons such as newly added RAM?
Try this next if you have not already.
littleshoulders [:-)

Restored 10.6 OS from CD and fails to Boot after Combo upgrade

I have a clean install of Lion on my internal drive and an external clone of the HD from the previous Snow Leopard install. The Clone worked until I updated via the latest auto update. I have App's and other settings to transfer to Lion from this clone so want to get it working so I can ensure all the App's are upgraded to work on Lion or are deleted.
After the external drive failed to boot I reinstalled the system from my Snow Leopard Install CD, not the 24-inch iMac (Mid 2007) restore CD.
I then used Auto updater to install the combo and other updates to 10.6.8 this booted fine until I upgraded Safari 5.1 and Java - the last items that came up on the software updater. Upon restart, the boot failed in the last portion of the boot and at this point the Apple emblem went away and the round circle with diaginoal line apeared.
On starting with the option key down, the clone disk 10.6.8 shows as being available, along with the internal Drive, for booting.
Starting with "command + S" gets through to the last line of the process then states "waiting on Root"
When compaired to a Snow OS that boots OK it is the last line of code before the curser is ready for entering a command.
Can anyone tell me what to look for or how to repair this error so that I can get my data across to Lion. Thanks

Well, in case anyone else has a similar problem I managed to fix the system by the following process:
I reinstalled 10.6.0 from the retail Snow Leopard CD. The drive Booted OK but I needed to be upgraded to 10.6.8 to use the migration tool so I then upgraded using the Software Update utility. Boot failed again at this point and could not be fixed by anything I did.
I then reinstalled 10.6.0 from the CD to try again, but the HD would not boot this time around.
I downloaded CleanApp by Synium Software (http://www.syniumsoftware.com/cleanapp/) on a commendation from the famous eBook, "Take Control of installing Lion" by Joe Kissell of TidBits. I used this from my Lion HD to remove all orphan files, PPC files and Apps, and other junk. Snow Leapard still not Booting after repairs by various disk repair utilities including Apples.
I Booted from my internal HD using Lion and ran SuperDuper to make a new Clone of the failed HD on a second external HD. Took a day and a night to run while I was at work, but the new clone would not boot at this stage so I ran SuperDuper again using the "Smart Update Backup" option. This just adds changed files or missing files to the clone. At the end of this process I had a running Clone that would boot on 10.6.0.
I Booted from the second Clone and used the Software Update utility then to up grade in the two stages the Auto system used to bring my OS up to 10.6.8. This was successful and I had a Bootable Snow Leopard with no old Apps from which to Migrate my data.

My 2011 IMac will not boot up past the White apple logo screen with the whirly circle

My 2011 IMac will not boot up past the White apple logo screen with the whirly circle. I have tried various commands but to no avail. does anybody have any advice?

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 fails to boot up

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