OS X 10.10.3 can't boot past startup screen

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Level 1

8 points

OS X 10.10.3 can't boot past startup screen

I've updated my 2009 iMac to OS X 10.10.3 and it can't be booted to the login screen after that. The progress bar will be stuck at 50% forever on the startup screen — the longest I've waited was about a day and the iMac was really hot as well. I tried getting into Recovery Mode and did a disk repair and it managed to repair 4 permission errors, but there's one permission that persisted and it says (Warning: SUID file "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAg ent" has been modified and will not be repaired). I rebooted again but it still can't boot past the startup screen.

Unfortunately, I can't reformat OS X because my backup copy from Time Machine has been outdated for a few months as I haven't bought another backup drive to continue using it.

One of the options that I could think of is to reinstall another copy of OS X from Recovery Mode, as it is able to retain my data files. But the problem is that my iMac has only 5 GB of free space, and it doesn't allow me to do that. Is there a way to use the Terminal in Recovery Mode to delete some of my apps and files so that I could install a copy of OS X? Or are there any other ways to solve it?

Any help will be greatly appreciated. Thank you.

iMac, OS X Yosemite (10.10.3)

Posted on Apr 11, 2015 7:41 AM

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Answer 1

Apr 11, 2015 8:18 AM in response to standard23

did you try a safe boot?

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Answer 2

standard23 Author

Level 1

8 points

Apr 11, 2015 9:53 AM in response to powerbook1701

Yup I've tried, but it still gets stuck at the startup screen with the progress bar at 50%.

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Answer 3

nomulous

Level 1

4 points

Apr 13, 2015 10:45 PM in response to standard23

I had the exact same issue on my mid-2012 rMBP after updating to Mac OS 10.10.3.

Do you have FileVault enabled by any chance? I solved the issue by booting into Recovery Mode, turning off FileVault using Disk Utility, and restarting. It took about 5-10 minutes to start after that but I ended up being able to log in, and after that the start up became fast again.

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Answer 4

standard23 Author

Level 1

8 points

Apr 16, 2015 8:28 AM in response to nomulous

Hi Nomulous.

Nope, I did not have FileVault enabled.

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Answer 5

standard23 Author

Level 1

8 points

Apr 16, 2015 8:42 AM in response to standard23

I've managed to solve this issue by using a very simple and straightforward method.

I remembered Macs have this nifty feature called FireWire Target Disk Mode by pressing and holding "T" on the keyboard the moment you turn it on. So I went to get myself a FireWire 800 cable and connect it to my MacBook Pro, activated FireWire Target Disk Mode on my iMac (Target) and browse the files from my MacBook Pro (Host). I deleted some files, recovered some free space, disconnect, reboot, reinstall OS X in Recovery Mode and — voila! — my iMac is back running OS X Yosemite with all my data files and settings again.

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