Yosemite: boot hangs at 50% percent

Just to correct a misperception here, command-R is NOT safe mode. Command-R boots you into the recovery partition (which only exist if you are on Lion or higher).

Safe Mode is invoked by holding down the Shift key when you boot.

I have tried holding the shift key and also I have did research and I have seen that the reason I cant go into safe mode is because I have a passcode

My story:

I have a late 2011 MacBook Pro with Yosemite. Has worked fine until just recently when it didn't. Would get stuck during boot, around 30-40%. Tried all the things suggested in this thread with no luck. Apple Hardware Test reported nothing wrong. Could get Internet Recovery started (would see spinning globe, pick a wifi network, and start downloading), but then system would crash after download was done before seeing recovery options. Took it to Apple store and they said video portion of main logic board was shot. Apparently there is a known issue with Nvidia chipset on late 2011 MBPs where it will overheat and fry itself. They replaced the logic board for free (even though I was out of warranty). Said it would have cost $530 if it were not for the known defect. They also verified that the $310 flat rate repair would have been an option (so it would have cost me $310, not $530). Flat Rate Repair is a GREAT deal and seems to be easy to get as long as the device does not have physical damage (drops/spills). They offer a flat rate repair for drops/spills for around $1200 (I forget the exact amount they said). So, morals of story are: the AHT is not nearly as comprehensive as the test they run at Genius Bar, and the Flat Rate Repair is a great option!

Hope this helps someone.

I upgraded 25 iMacs to Yosemite, and it has developed into an annoyance. If the machine boots up and the progress bar reaches about 30% - 40%, the display SHOULD dim and the cursor should appear at the top left corner. If this doesn't happen, don't bother waiting, just do one or all of the following:

• Holding down Option + Command + P + R, At boot-up.
• Holding Command + R and repairing disk permissions.
• Booting into safe mode and restarting.
• Restarting the machine.

Although these solutions work, this is absolutely redundant especially when managing multiple machines. Simply put, these machines are meant for the enterprise environment. Even in the case of them being personal computers, are you honestly ok with investing so much money in a machine that requires you to remember a certain key combination in order for it to work? I manage close to 130 Windows machines in the same building and not a single one has prevented a user from being able to log in. Just saying...

I have an ssd installed in my macbook po, but it still, stucks at the loadig screen, in safe boot, it's even slower...

Does anyone know if Apple are going to do anything about this problem? It seems to have been dragging on for long enough and I'd consider this to be a serious issue and I can't understand why Apple seem to be ignoring it.

I have tried almost everything mentioned in this post and the problem keeps coming back. I thought Macs are meant to be more reliable! I have 300 win 7 PCs at my school, they work like a dream. But the 20 Macs are wasting so much of my time, not booting is a major issue!

I keep applying OSX updates hoping it will resolve this issue, but no I keep on getting told that the Macs are not booting again.

Resolution is to replace them with windows PCs, at least they boot up!

The Solution to the Half-Way Stuck Grey Apple Load Bar is as Follows:

1. Start with a PRAM Reset:
   • Power the Machine Off (Hold Power)
   • Power the Machine Back on and Immediately Hold CMD+OPTION+P+R
   • The Machine will Chime and Reboot
   • Feel free to do it two or three times, it won't hurt the Machine
   • Let the Machine Boot Normally
2. Then when the Load Bar remains stuck, hold the power down and boot into Single User Mode (CMD+S at boot)
   • When the command line appears, wait for bash to appear.
   • Type: fsck -fy (press enter, command should be on the screen, $ /sbin/fsck -fy)
   • Let it think for some time (~1 min) then when bash reappears, type the next command after fsck -fy: mount -uw (press enter)
   • Let it run through, then when bash reappears - type exit.

Enjoy the login screen and problem solved. Please mark this as Solution for other users to receive.

I just wanted to add that I was having the same problem. Old 2008 Mac upgrading to the newest Yosemite. I tried booting in Save mode, recovery mode, cmd/option/P/R and the rest. I finally gave up and left it hanging on a solid white/gray screen. 20 minutes later, I got a "completing installation" message and I'm good to go. Maybe leave it alone and come back to it, is all you need.

Thanks for the workaround!

Reseting NVRAM with CMD+ALT+P+R worked for me without having to go into safe mode.

My MacPro was hanging at boot since the update from Mavericks to Yosemite.

got stuck at 50% on the progress bar.

Thank you very much @Old Toad. I have had this issue twice, and I was able to solve it by reinstalling OSX. However, I had this issue again, so I chose to simply verify and repair disk permissions and that solved the problem. You saved me having to reinstall OSX again. Sincere Thanks 🙂 (btw this is my first time owning an apple product. I'm extremely happy with it. Got it for cross-platform development testing and actually turned out loving this Macbook (late 2009).)

Hi,

I have the same problem; I'm wondering how you solved it.

Thanks!

We just had this issue yesterday with two Mac Minis after some power issues last week. We tried:

• Resetting the NVRAM
• Booting in safe mode
• Booting in recovery mode and repairing permissions/disk
• Unplugging everything external from the Mac (monitors, audio, etc.), powering on, then plugging everything back in after about 30 seconds. This option worked!

Normally, resetting the NVRAM works, though the last option had not occurred to me at first because this Mac was not a Macbook Pro. The Macs I had issues with were Mac Minis, so it kind of threw me. I'm just glad I didn't have to reinstall everything.

My exact problem!! Many thanks.

I have a new MacBook Air and am having this problem (status bar fills between 30 and 50% 0n startup). I have tried virtually all of the solutions (start up key combinations) with no success. Was hopeful tnethers solution would work, but after entering mount -uw and then exit after bash reapers, it hangs after "en1: promiscuous mode enable succeeded"

Have an appointment with the genius bar tomorrow evening, was hoping to avoid that. Will try and update my solution after.