Q: Macbook Pro freeze after login (Yosemite)

I need the hard drive in the mac not as usb to get the permissions to highlight ill see if it will reboot now following your directions

ok so I finally got the system to boot...finally, and have done the NVRAM had to do that a gazillion times to get the system to boot.

So far no issues will let you know if it stays ok

Thanks

I had the same problem, i finally find the way to revert the encryption of FileVault.  What i did is, make a boot Yosemite USB Key with another Mac, boot the Macbook with USB, by maintain ALT key at boot.  At the install question, there is and option to start DISKUTIL on top menu. By  selecting system disk and unlock it, i make all the repair i can, and after that, there is the option to decrypt the disk. After selecting that and enter the password, the decrypt start in background. I can then reboot the computer.  I can login without any problem, the decrypt of the disk continu, and i hope this nightmare stop.  

To all the people thinking FileVault is the issue:

I have had FileVault encryption disabled before upgrading to Yosemite & also once Yosemite was installed. This goes for the other six iMacs in my office that were upgraded to Yosemite. The issue at hand, can not officially point to FileVault2 being the cause. The reasoning for this is due to the fact that I have experienced the same problem as others on this post, without having FileVault encryption enabled. If I had time to go through numerous system logs, maybe I could pinpoint the exact cause. For now, and as I have previously posted, PRAM flashing, running DSKUTIL, & shutting down completely when not in use, has been the most efficient fix.

I can confirm romiz80 observation with FileVault2 (see my post earlier in this threat). I was absolutely not able to login after turning FV2 on. After several attempts with disk repair, etc. I could finally log in, probably after the third PRAM/NVRAM reset. I turned FV2 off and immediate everything was fine and the issue is gone since than...

The thing with the the "third flash of PRAM/NVRAM, the Mac loads on cold boot correctly and you can login" info was new to my, thanks for the hint.

I understand what you are saying. But as I explained in my last post, I never had FileVault enabled prior to upgrading to Yosemite, or with Yosemite, and I still encounter the errors. If I did enable FV2 and encrypt my HDD today, I am sure I would experience the problems you had. This is mainly because (and this is my opinion) whatever is causing these annoying boot/login issues on Yosemite, must be corrupt data in the disk cache. Having the disk unlocked and then encrypted, may possibly be writing Post-Yosemite data/instructions to the disk cache, that is causing the underlying issues.

OK so after I did the NVRAM reset and disk utility file permission repairs etc. and shutting down the macbook overnight, today I go to log on and I get a white screen...no apple logo, no startup, nothing.

I then redid the NVRAM reset holding the P, R, command, option and start button (i held this down until it chimed 4 times as 1 did not clear it) The system came back on.

It has improved. At least its now moving in the right direction and doesn't appear to be randomly freezing anymore.

I am facing the same issue in my organisation.
The scenario was that we had a power failure and our mac mini 2012 got shut.

On restarting, all of them with Yosemite got stuck at boot screen.

What solved the issue was clearing/resetting the ram
(cmd+option+p+r)

and then restarting the mac holding (alt+r)

(keep holding alt+r after the mac starts to boot for a couple of minutes)

if it doesn't work, start mac in safe mode(cmd+r) and restart it from there and then hold alt +r

I am having the same problem on two machines: eight 2010 iMac and a 2012 MacBook Pro. These tricks such as resetting envy RAM work occasionally, but both machines are essentially crippled. The iMac freezes regularly and has to beshut down by cutting the power. After that, it usually takes many attempts to get it to boot again. We are desperate for a solution. A clean reinstall of Yosemite on both machines did not help at all.

same here my macbook pro retna hangs on shut down

its an OS X fault apple need to fix this

before i had mavericks and i had kanel  panics all the time apple did nothing

as soon as i got yosamite downloaded i have none so you tell me whats going on apple please

This is a persistent problem for me and I am surprised that there are relatively few people complaining about it (compared to the WiFi issues with Yosemite for example).   The first time this happened to me was a few weeks after installing Yosemite and I reinstalled my whole system on my 2014 MBP.  This seemed to fix it...

A few weeks ago the issue reappeared and I was able to reboot by resetting the SMC each time it occurred.  In my case resetting NVRAM did not work.

Now though, no single thing is working for me, although after multiple SMC and NVRAM resets, followed by an attempted boot into Recovery mode my system eventually boots.  For some reason it won't even finish booting into Recovery mode but hangs at about 75%, yet when I shut the system down and then reboot normally half the time it works.  The other half of the time it works after doing this another 1-2 times.

For me though, when the system seems to be running normally and I shut the computer down overnight, it also won't boot the next day. 

This is such a pervasive issue that I hope Apple has taken notice and will fix it with the upcoming update.  I really don't want to go back to Mavericks.

I managed to get my two machines working by doing a clean install BUT NOT REINSTALLING MY APPLICATIONS. Crazy, I know. I then manually reinstalled my App Store purchases (very easy) and used old installer discs to reinstall essential applications. But I lost a lot of other stuff, and will eventually have try and get activations reset on other software. A horrible task, made more horrible because Migration Assistant sales more often than it succeeds. I'm currently in the middle of doing the same thing on a third machine. The other two now seem to be running well.

Go back to Mavericks? If that option were actually available, I would have leapt at it.

FV is not the sole issue. I have numerous Macs in my office that do not use FV2 disk encryption.

my macbook pro rent freezes on shut down for a few seconds is that normal. thats what apple care said it is normal for that to happen

and it still happens on 10.10.2 any help please

This issue happens with or without FV2 encryption enabled.