Grey screen on restart after Yosemite upgrade !

az1103

Try powering down and rebooting but hold down SHIFT key to go into Safe Mode.

Keep holding the SHIFT key. It may take a while. Be patient, until the computer does its Venetian blinds thing and goes into Safe Mode

Background: I had started an install last night about 10 hours ago on a MBP 17 mid 2010 with 8 GB. Never took.

Finally booted into Safe Mode. Did Numbers, Keynote, Pages updates.

Then kept my fingers crossed and rebooted. It works fine. Note - I am liking Yosemite so far.

I had this problem also. Subsequently the problem has become solved (mysteriously). In the following discussion I will describe my situation, actions and the results. Hopefully it may help some of you. The iMac involved is a 2012 vintage.

1. On the second reboot from the Yosemite install sequence the iMac just seemed to stop processing the install. Only a gray screen was showing. eventually it timed out and went to sleep.

2. Subsequently I tried removing power (unplugged the power cord). Then rebooted. It started with the gray screen with the apple icon in the middle and a progress bar underneath. The progress bar proceeded showing progress until about 1/3 complete then it reverted to a gray screen and eventually showed a mouse pointer in the upper left. The displayed pointer responded to mouse movements.But nothing else was visible on the screen.

3. Tried restarting several times with the same results. During all this time there were complaints reports to the group about slow internet transfers for Yosemite downloads. (Note I thought that my download had completed by this point.)

4. I was concerned that there may be disk problems so I followed the advice for using the Internet Recovery mode (Boot up with Command, Options, and R simultaneously pressed.) In this mode I ran the tool for checking the disk. The disk checked okay.

5. I decided to wait awhile in case the internet load somehow was affecting the install. For example, some handshake time-out value perhaps was being exceeded.

6. About three hours later I decided to try to reboot again. This time I had the same results initially except that the display did not time-out and after a delay of several minutes it displayed a new screen with a label above the progress that said something like "Completing installation."

7. The install then completed and the computer is working fine with Yosemite. However, upon subsequent reboots the computer still seems to pause at this same point but does continue after a few minutes to complete the reboot.

Hope this helps some of you.

Strangely enough, this worked.

Here is a small tid bit for you all. Yosemite takes quite a while to download, a couple of hours in most cases. Do not have any other Application open when you update or upgrade (ever). Over the years I have found in my particular case I restart the iMac before I download anything. Yes I know this isn't really a must but it's just the way I roll. If your HD is loaded and you are low on space remember this will slow you down a lot when upgrading to a newer Operating System.

My last tid bit is this I (never ever) use my computer to do anything else when downloading, Never Interrupt a Download in progress with another application open during the download. It may be just me but I have never ever had any issues with any Mac over the years and trust me I have owned a lot of them and they all still run and work right along.

CHEERS

DON

I think this is happening is due to the video display not being set correctly after the update. When I logged in under safe mode, the iMac appears to have went through a process of setting the display correctly.

I had a similar problem. Found that if I removed my McAfee anti-virus by booting into Safe Mode (hold shift after a restart), and running its uninstall program it all worked.

I am seeing exactly the same thing - grey screen. Apple. progress bar anywhere between 30% and 50%

I upgraded on Sunday and MacBook Air has been running fine on Yosemite. This morning it rebooted itself (I don't know why) and have been unable to get it to load OS since.

Safe mode - fails (my fingers are going to sleep after 15 mins)

Verbose Mode - fails

PRAM reset performed

I can run recovery mode and I have verified and repaired the disk.

I have once managed to get it to the login screen where it noted that the Mac had crashed but I was unable to click on either the Open or Cancel options (spinning wheel and coloured wheel).

My last option will be to try and reinstall OS once I am at home as the WPA/WPA2 Enterprise authentication at work won't allow me access to the wireless network.

I have never had any problems with a Mac I have owned - first time for everything, but this is annoying and (it would seem) not uncommon...

I had a similar problem. I also tried the PRAM reset etc. in the end I found that if I removed my McAfee anti-virus by booting into Safe Mode (hold shift after a restart), and running its uninstall program it all worked. Or, reinstall previous OS X and remove McAfee then try reinstalling 10.10. It may be that instal of 10.10 doesn't like programs resident in the menu bar, or perhaps other anti-virus programs. What I do know is that when I took out McAfee, it all worked well.

It won't boot to safe mode. That screen is where it has got with safe mode !!

I am sure that something is causing it to hang, but unless I can get safe mode to load I can't find out what. It definitely isn't McAfee.

Thanks

Ah well... good luck!

I think that there are two different problems here; however, they are both valid problems. First, there seems to be a problem with McAfee and Yosemite that is cured by the upgrade of McAfee. They put out an update that seems to coincide with the release of Yosemite. Second, the grey screen upon booting. Booting into safe mode by itself does seem to correct the problem. I think the grey screen is occurring because the display is not set correctly. I am betting that if it were, then we would all see a login screen. I booted to safe mode one time and the problem was corrected. I think that TimUK may be having a different problem based upon his comments. Try removing any additional storage devices or printers if you haven't already. I would surmise that your system is hanging up as a daemon is starting. It might help to boot into logging mode with Command-L to see if you can see where it is hanging up.

I would tend to agree on the multiple issues with similar symptoms.

For some strange reason I have used Shift-Command-V and the MBA loaded to the Login screen. I have logged in as Admin and I now have a spinning coloured wheel. Sods law says that I will be leaving work for the day just as it looks like it might actually load a desktop !!

I meant to mention: Logging and Verbose mode - neither is displaying anything.

I've had the same issue and despite clearing the PRAM and powering on and off repeatedly this is what has (at least temporarily) resolved my issue:

I've done this 3 times and sometimes it works right off the jump other times I've had to wait a bit and try again or power off and try again, once the start up screen is frozen hit Command : Option : Shift : Esc and a window should pop up "You restarted because of a problem..." from there you can go to your desktop. I haven't found an actual resolution to fix the problem but this does get you into your computer.

Hope this helps!

I posted this in another forum here: Yosemite Upgrade - iMac mid-2011 - Stuck on white progress bar screen at about 50%

I have a Mid 2011 iMAC and encountered the grey screen of death and the disappearing progress bar from **** when installing Yosemite. Majority of the problem stems from Yosemite installation not being completed and lagging in the background upon reboot. Here are some easy fixes:

1. Restart your computer by holding the power button for 10 secs. Upon reboot and chime hold down the SHIFT key. Be patient, for it can take some time for the Safe Mode screen appear.
2. Once in Safe Mode you should see a Yosemite completing installation pop-up box appear. Let the Yosemite run its final installation piece and restart normally by selecting the option form menu bar. Do not use the power button to restart your computer once in Safe Mode.
3. Once you restart, there should be no more grey screen or progress bar issues. Login as normal to your user profile

If you have tried this to no avail, then you can reboot and run Disk Repair utility or try a fresh reinstall of Yosemite by holding down the OPTION key upon reboot and chime. You may also try resetting the NVRAM an PRAM by retarting and holding down SHIFT + OPTION + P + R upon reboot and chime.

Good Luck