iMac Can Only be Booted in Safe Mode (Shift Key held down)

Per your request, here are the EtreCheck results:

Hardware Information:

iMac - model: iMac11,1

1 2.8 GHz Intel Core i7 CPU: 4 cores

8 GB RAM

Video Information:

ATI Radeon HD 4850 - VRAM: 512 MB

System Software:

OS X 10.8.3 (12D78) - Uptime: 0 days 21:11

Disk Information:

WDC WD1001FALS-40U9B0 disk0 : (1 TB)

disk0s1 (disk0s1) <not mounted>: 209.7 MB

Macintosh HD (disk0s2) /: 999.35 GB (244.64 GB free)

Recovery HD (disk0s3) <not mounted>: 650 MB

OPTIARC DVD RW AD-5680H

USB Information:

American Power Conversion APC ES 750G FW:859.K1 .A USB FW:K1

Apple Computer, Inc. IR Receiver

Apple Inc. Built-in iSight

Apple, Inc. Keyboard Hub

Apple, Inc Apple Keyboard

Apple Internal Memory Card Reader

Apple Inc. BRCM2046 Hub

Apple Inc. Bluetooth USB Host Controller

FireWire Information:

NewerTech Voyager Q OEM ATA Device 00 800mbit - 800mbit max

disk2s1 (disk2s1) <not mounted>: 209.7 MB

750GB (disk2s2) /Volumes/750GB: 749.81 GB (749.18 GB free)

Kernel Extensions:

Problem System Launch Daemons:

[failed] com.apple.coresymbolicationd.plist

Problem System Launch Agents:

[failed] com.apple.coreservices.appleid.authentication.plist

[failed] com.apple.printtool.agent.plist

[failed] com.apple.tccd.plist

Launch Daemons:

[not loaded] at.obdev.littlesnitchd.plist

[not loaded] com.adobe.fpsaud.plist

[not loaded] com.adobe.SwitchBoard.plist

[not loaded] com.barebones.authd.plist

[not loaded] com.crosscountrysoftware.Online_Bible_Installer.plist

[not loaded] com.google.keystone.daemon.plist

[not loaded] com.justsystems.OnlineUpdate.plist

[not loaded] com.micromat.TechToolProDaemon.plist

[not loaded] com.microsoft.office.licensing.helper.plist

[not loaded] com.smithmicro.schedulerdaemon.plist

[not loaded] com.splashtop.streamer.SRServiceDaemon.plist

[not loaded] com.stclairsoft.DefaultFolderXAgent.plist

Launch Agents:

[not loaded] at.obdev.LittleSnitchNetworkMonitor.plist

[not loaded] at.obdev.LittleSnitchUIAgent.plist

[not loaded] com.adobe.AAM.Updater-1.0.plist

[not loaded] com.adobe.CS5ServiceManager.plist

[not loaded] com.brother.LOGINserver.plist

[not loaded] com.epson.epw.agent.plist

[not loaded] com.google.keystone.agent.plist

[not loaded] com.justsystems.launchd.UpdateChecker.plist

[not loaded] com.micromat.TechToolProAgent.plist

[not loaded] com.smithmicro.cleaning.quickbackupcheck.plist

[not loaded] com.splashtop.streamer.SRServiceAgent.plist

[not loaded] net.culater.SIMBL.Agent.plist

User Launch Agents:

[not loaded] com.microsoft.LaunchAgent.SyncServicesAgent.plist

[not loaded] com.smithmicro.cleaning.schedulermailer.plist

[not loaded] com.valvesoftware.steamclean.plist

[not loaded] ws.agile.1PasswordAgent.plist

User Login Items:

LaunchBar

Default Folder X Helper

Caffeine

MagicMenu

CrossOver CD Helper

VMware Fusion Start Menu

Dropbox

ATOK23

Google Updater Helper

3rd Party Preference Panes:

Default Folder X

Flash Player

Flip4Mac WMV

Growl

TechTool Protection

Internet Plug-ins:

Flash Player.plugin

FlashPlayer-10.6.plugin

Flip4Mac WMV Plugin.plugin

GoogleOneClickPlugin.plugin

iPhotoPhotocast.plugin

JavaAppletPlugin.plugin

OfficeLiveBrowserPlugin.plugin

QuickTime Plugin.plugin

SharePointBrowserPlugin.plugin

Silverlight.plugin

SpeedDownload Browser Plugin.plugin

Unity Web Player.plugin

User Internet Plug-ins:

fbplugin_1_0_3.plugin

Google Earth Web Plug-in.plugin

SOEWebInstaller.plugin

Bad Fonts:

None

Top Processes by CPU:

12% Dropbox

1% EtreCheck

1% WindowServer

0% imagent

Top Processes by Memory:

80 MB Google

74 MB WindowServer

72 MB Dropbox

49 MB Finder

49 MB Dock

41 MB LaunchBar

33 MB mds

33 MB SpamSieve

33 MB coreservicesd

25 MB CVMCompiler

Thank you for your detailed and helpful reply.

JustSystems makes ATOK, the Japanese language input method that replaces KOTOERI. It's been installed for a couple years now. My wife uses it daily in her User. It's never given us a problem.

I have no ideal how SIMBL got installed, so how would I go about removing it manually?

The really strange thing in all of this is, I've not installed any software recently. For example, that Smith Micro software you suggested I remove, I installed it a few years ago. I ended up never using it. So if it was the root problem, why would it suddenly active now?

While awaiting your reply to my previous post, I made a Carbon Copy Cloner clone of my iMac's internal HD to an external fw800 drive. I ticked the CCC preference that makes checksums, to ensure there would be no corruption during the clone. I made the clone because I just wanted to see what would happen if I cloned my HD and then tried to boot off the clone.

When the cloning was complete, I proceeded to uninstall Smith Micro Spring Cleaning and Splashtop software on my iMac's internal HD (into which I was booted in Safe Mode at the time), and then I looked in Library/Launch Agents/to delete out some of those plists you said I should get rid of. I also did so in the library/Launch Daemons/folder too. Again, those deletions were of course on my iMac's internal drive. I did not do the same on my clone.

I then opened the System Preferences and I then chose my external FireWire drive as the start up disk, and then I restarted. The boot sequence was at first exactly as the boot sequence of my internal drive. Specifically, I would see the gray screen, followed by the Apple logo, followed by the spinning spiked wheel, then the spinning spiked wheel would vanish, then the Apple logo would vanish and reappear. There was an enormous amount of disk activity too, just like when booting from my iMac's internal hard drive. To my delight, eventually the clone booted to the desktop. For good measure I've been restarted and this time too the clone booted to the desktop, but more quickly than before.

I then decided to open System Preferences and select my iMac's internal hard drive as the start up disk, and then I restarted. But as in previous cases when I tried to boot off the internal drive, there was a lot of disk activity and it took a long time, but it never booted. However, there was one difference this time. This time I saw some strange horizontal line artifacts appear in various places on the screen, just as you see in the photo I took today here:

https://www.dropbox.com/s/19vgt0zvip945ri/Photo%20Apr%2018%2C%206%2001%2030%20AM .jpg

Eventually the hard disk activity completely stopped, and the computer never booted. What you see in my photo is all I saw after the disk activity stopped.

I've then held down the power button to kill power to the iMac, then I pressed the power button to start up, then I held down the option key to chose my external FireWire drive, and a few short seconds later it booted to the desktop without problem. And again, keep in mind this external FireWire drive is a perfect clone of my iMac's internal drive!

In light of this, what do you now suggest?

I will follow your advice today after I get off work and then report back.

In the meantime, this URL should work so you can view my screen photo:

http://tinyurl.com/bqpwk2r

(I don't think this forum likes long URLs.)

I also have one question. While booted into my Firewire clone drive today, I launched Disk Utility but was unable to Unmount my iMac's internal HD. It said I need to first quit any apps that the internal HD may be using. But how in the world do I know that? There were no open apps stored on the internal drive that I know of.

I want to unmount the drive and then test my clone, just for my PEACE OF MIND. I know the theory. In theory, my clone should be 100% OK. But for my own peace of mind, I want to use my clone with the internal drive unmounted, so that I can see with my own eyes that all apps are launching off the cloned drive, with no dependencies whatsoever on data that resides on the internal drive.

So again, please tell me how I can boot off my firewire drive and then successfully unmount my internal HD.

Thank you for all your kind help and assistance to date.

Well I'm at my wit's end. I can no longer boot into recovery, neither by CMD-R nor by holding down Option and choosing that as the boot drive. Furthermore, I can no longer boot from my bootable 8GB USB thumb drive which has the Mountain Lion ESD installer on it. Moreover, I have a 1TB external FW800 drive that I cloned a couple years ago when I used Snow Leopard. That drive always booted just fine on this iMac, but now it won't.

Nevertheless, I can still boot my iMac's internal drive when I hold down the shift key. Ditto for the clone I made of that on yet another external fw800 drive. I can also copy files to and from any of my drives without error. I even copied files between my two FW800 drives without problem.

Yes, I reset the SMC and PRAM. That did not help.

Yes, I checked the SMART status, both in Disk Utility and Disk Warrior 4.4. No problem reported by SMART. But Disk Warrior would not rebuild the directory due to a Mac OS error, or so it reported. I tried it unsuccessfully on my internal HD and on the external clone.

This makes no sense at all. I've been up and running with this iMac for years, and now it suddenly acts like this.

Any further though and suggestions would be greatly appreciated.

Thank you.

While booted from my iMac's internal HD via Safe Boot (shift key held down at boot time), I ran TechTool Pro 6.0.6. A SMART scan shows nothing wrong. I ran the Surface Scan for 6 hours, but it hadn't found a single bad block during that time (although it says it would take another 4 hours to fully scan the 1TB drive). Memory tests passed, as did Video Memory tests. No problems reported in the File Structure test.

I even ran Apple's Disk Utility again, but again it cannot find anything wrong!

In light of all these tests passing with flying colors, it makes no sense why I am only able to boot with the silly Shift Key held down!

Since Disk Warrior 4.4 failed to rebuild the volume directories on my internal HD and my external clone, I gave TechTool's "Volume Rebuild" a shot. Since I was booted from my internal HD, I could only run Volume Rebuild on my external FW800 clone. But it the directory rebuild was successful, and at the end of the rebuild sequence it gave me a comparison between the Original Directory and the Rebuilt Directory. There were only 4 differences reported, and all were highlighted in Green as "favorable changes" (there were no "unusual changes"):

CATALOG B-TREE

Used Nodes

Old: 55,870

New: 49,272

Free Nodes

Old: 9,666

New: 16,264

EXTENTS B-TREE

Used Nodes

Old: 5

New: 4

Free Nodes

Old: 2,811

New: 2,812

I then proceeded to replace the directory on that drive. I then made sure that external clone was the startup drive and I restarted my iMac. I did not press the Shift key during boot time. Sadly, my external clone drive, even with that pristine new directory, never booted to the Desktop. Just like I reported to you before:

• I see the blank gray screen

• I then see the Apple logo

• I've then see the spinning spiked wheel beneath the Apple logo

• Then the spinning spiked wheel vanishes and the Apple logo vanishes for a brief instant and returns.

• There is even more disk access than normal at this point, mainly from my external FW drive (from which I am trying to boot) but I can also hear access from my iMac's internal drive too.

• After several minutes of churning, all drive access suddenly stops, and I am left staring at a gray screen with the Apple logo in the middle, with no arrow cursor or mouse movement indication.

• I then have no choice but to hold down the power button on the iMac to turn it off, then I let go for a second, then I press it to start up the iMac, then I quickly press Shift when I see the gray screen, and this time it boots off my external drive into Safe Mode!

Folks, I really need to obtain some further assistance from you on this. Safe Boot is fine and well, but I can't watch YouTube videos in Safe Mode, some graphics either don't display or are corrupted or flicker in Safari, and after using my iMac in this condition for a while, I do get an occasional freeze, which forces me to hold down the power button and reboot. All said, I shouldn't be condemned to live out the rest of my computing life in Safe Mode.

Your kind assistance in offering further advice and tips would be greatly appreciated.

Thank you.

But as I mentioned before, I do have such a "Mountain Lion disk without any of the extra stuff installed." As I mentioned previously, I have such on a bootable 8GB USB thumb drive. No "extra stuff" is on there. It's the raw installer.

True, in my earliest post I said that I was able to boot from that USB thumb drive and reinstall Mountain Lion on my iMac's internal HD (which didn't fix the problem). But when I later tried that (a day later), I couldn't boot off that thumb drive anymore.

Furthermore, I originally said (earlier in this discussion) that after making a clone of my internal HD to an external FW HD, I could boot ONCE off that external FW HD without having to resort to the Shift Key. However, on every subsequnt reboot into that FW external, I was never able to boot it again WITHOUT the Shift Key.

No, I have not yet tried the painfully slow optical disc that originally came with my iMac. But I will do so tonight after work.

For now, I can report that there is in fact nothing wrong with my USB thumb drive or my Firewire external clone. You see, I have a March 2009 3.06GHz iMac DuoCore at the office, which is also running OS 10.8.3. That office iMac is problem-free. I booted that iMac off my USB thumb drive in seconds. I then switched on my external FW HD (the clone I made of my iMac's internal HD at home) and I proceeded to check it with Disk Utility. But there were no problems found. I then exited Disk Utility and set the external FW drive as my Startup Disk. I was able to boot the iMac perfectly with it, no Safe Boot required!

So what do you suggest in light of this?

I have not made any reporting mistakes thus far in this discussion, so to determine what I have done would be to merely re-read through all I have written to date. But sparing you that drugery, I will summarize. I was able to boot off the Recovery Partition of my iMac's internal HD (my problematic iMac at home) ONCE. But after that I was not able to boot off it again. (I reported that here.) And because I cannot boot off my iMac's internal HD's Recovery Partition (when holding down CMD-R), nor can I now boot off my USB Thumb Drive (which has the raw Mountain Lion installer), I cannot format my internal HD and subsequently install 10.8 on it. And once again, keep in mind that my USB thumbdrive boots my iMac at the office perfectly fine, and so does my external FW HD clone (without my having to hold down the Shift Key).

Therefore, since I do not have a Mountain Lion DVD installer (nor does anyone that I know of), in light of the fact I cannot boot from my Recovery Partition, how then should I go about formatting my iMac's internal HD and subsequently installing Mountain Lion on it?

I must say that I am skeptical if that "test" would do much good seeing that my perfectly good USB thumb drive boots my iMac at the office but it won't boot my iMac at home.

Taking in my computer is a last resort mainly because I use it so much, as does my wife, and we are still using it (albeit barely) while in Safe Mode. Taking it in to an Apple store would be a 1 hour drive, they would surely keep it for a week, and then would need to make yet another trek back to pick it up. It's a lot of hassle. If the problem is hardware, I suppose there would be no other choice. But yet another problem is that although I have AppleCare, such lasts only 3 years. My AppleCare is now expired (I bought the iMac in Nov. 2009).

It's a real mess.