Yosemite Upgrade - iMac mid-2011 - Stuck on white progress bar screen at about 50%

This worked flawlessly - I left mine (27" iMac late 2012 - 2.9GHz Intel Core i5) sit idol for about 1 hour and restarted. I am not that patient so I had to take the leap of faith. Restarted as you instructed and the rest of the install then took about 5 minutes tops.

Everything seems to be running as normal so far. 🙂

I held off installing Yosemite over my Mavericks on 2012 iMac because of all the negative feedback I've read.

Tonight I bit the bullet and did it. Whadya know, it ****** stopped halfway along the progress bar on the final part of the install on the grey apple screen.

I left it for about 30 minutes and nothing was happening so I did what was suggested after I took a very long deep breath...

Held down power button to shut off the iMac

Waited 10 secs

Restarted the iMac

Held the R key down as recommended. Actually this didn't seem to do much because once the boot up started and the progress crawled to the halfway mark, it suddenly shot across the progress bar in no time...then I was there... the Yosemite log in screen.

Thank you so much for the advice, SATopWater. You gave me the courage to press the power button against all instincts during what seemed to be only a half finished system install.

Shame Apple. Half baked installation procedure. Not what I expected.

Yes the Solved solution worked for me as well, iMac mid-2011.

Thank you SATopWater.

Had 2 iMacs "hang" at 50% for 16 hrs. Sparkleberry resolved their problem installing. Since have upgraded 2 iMacs & 1 Macbook successfully.....after downloading, & before installing, I turned off wifi & removed as many logins as I could....had no problems with all 3. Thankyou, Sparkleberry!!!! I would have tried SATopWater next. Liked the idea of Safe Mode with Sparkleberry....don't know why except I'm not technical & looked good way to go. Now have upgraded 6 macs to Yosemite, first one soon after Yosemite released, and that was a nightmare. So waited months before doing remainder hoping there would be a solution to an Apple problem, but eventually had to bite the bullet!

I have a mid 2011 iMac and was upgrading to Yosemite and the progress bar froze in the reboot phase when it was at about 50%. After an hour or two, I powered down by holding the power button. I then unplugged all peripherals (ext backup drive; printer; wifi usb plug in for Wacom tablet etc) and then started up again and all seemed to go through fine.

Just in case it helps someone else!

Does restarting the computer delete your previous files.

To SATopWater. Thank you so much for your post. This worked for me perfectly. Still the same problem in June 2015!! So glad I found this.

Thanks. This Helped me.

Awesome! Worked great!!!

Thanks so much for this advice, it worked perfectly. The key item of advice is to be patient while holding the shift key. I would never have been so patient otherwise.

I too have a mid-2011iMac and I cringe whenever there’s a Yosemite update. The updates work seamlessly on my MBA and MBP and are a white screen nightmare on my iMac.

I’ll print these instructions for future reference.

Thanks to all who take the time to post such helpful information, tips and advice.

Thank you for posting this. Apple should give you a life-time supply of computers for being more helpful than they are.

wow woW wOW WOW!!!! My Macbook Pro 13inch - Mid 2009 Needed this badly!!!

That was too easy... THANKS TO SATopWater on Oct 17, 2014 12:41 PM

Who said

"I'm not recommending this to anyone, just thought I'd report on what worked for me:

- Let Yosemite upgrade sit at the white progress bar screen at 50% for 4 hours.

- Once I was nearly positive it wasn't doing anything like writing to the hard drive...

- Held power button for 10 seconds to turn computer off

- Waited about 10 seconds again

- Turned power on and held Command R (It took about 3 minutes to boot)

- Clicked on WI-Fi symbol on upper right and turned off Wi-Fi

- Selected restart from the System menu option

- Computer rebooted and finished the upgrade

I have since rebooted (twice to be sure) and run a few things and all seems fine at this point."

BY THE WAY, I held the left Command Key + R down BEFORE i Press the power button, and then WAITED!! for what seemed like ages with them held down, but it eventually went to recovery mode.

Thanks again!!! Perfecto!!!

APPLE!!! YOU ARE A JOKE!!! THIS HAS BEEN A PROBLEM FOR OVER A YEAR!!!!

Thanks for sharing this tip! I have an Early 2009 Macbook and the first time I tried upgrading to Yosemite in October 2014 I rolled it back to Mavericks because my computer only spun the Apple Beach Ball of Death, but after trying your tip it's working like a champ (aside from the performance snags as it is "Optimizing" mode upon first use of the system). Thanks again!

PERFECT!

Thanks heaps

This worked perfectly.

After the first restart, your MAC will asked if you want to restore - do a cmplete install etc. This is the screen where you disable wifi and the from system menu n top left hand corner select - restart.

worked a treat.

cheers for the post bro.

RyanManUtd wrote:

You guys were brilliant !

The SATopwater CMD-R method did not work for me bcos for some reason, the wifi icon did not appear and instead it ask me whether I want to use time machine.

So I shutdown again and use the shift key method, the the progress bar very fast moves to the right and after typing in the password, the screen kept flickering.

Then I do a restart and everything looks fine. So far so good.

Except the Time Machine icon is no longer on the task bar. How do I get that back ?

Thanks

Thanks, that was on 6-May-2015 when this problem was already solved.

Now on 25-July-2015, suddenly it got stuck at 50% again !

This time I just did the following:

1) press and hold the power button for 10 seconds to OFF the system.

2) press the ON button again to ON the system (this time I did not press any shift ket or and cmd-key, just the ON button and let it go ... )

And the progress bar moved very fast from left to right ... and system back to Normal.

Anyone knows why this is happening/recurring after 3.5 months ?

Is this sign of potential Hard Disk failure ? To be sure, I went to Disk Utility and and do a Verify Disk and the hard disk is OK ...

Anyone knows why this is happening/recurring after 3.5 months ?

Thank you ..

Cheers