boot very slow after installed Yosemite

That is second time I'm having the same problem. First time I tried everything and had to installed Yosemite again. Never had this issue before on Snow Leopard, Lion, Mountain Lion and Maverics with the same MacBook Pro. Everything is so freaking extremely slow, can't do anything.

mid 2011 27" imac.

I have successfully rebooted only once or twice since upgrade to 10.10.1 - to make matters worse I also got the horrible wireless problem - it is essentially dead. I have a netgear extender and was hoping that I could plug ethernet into that and get around the wireless issue but now I am unable to boot. I do not have a startup USB - reformatted it a couple of weeks ago to use for something else. dumb. To be fair I have killed startup probably after not more than 30 minutes. Progress bar quits about 1/2 way through.

I have tried SMC reset, NVRAM reset but so far no joy. I did do the disk utility stuff which resulted in a successful repair. No idea what the next step is. I was thinking about shelling out 99 for Disk Warrior but since I don't have another mac I'm not sure I can make a startup disk with it - unless perhaps it comes as an ISO file. Anyone have any idea about that?

Thanks,

Fred

Uninstalling McAfee also worked for me and a bunch of other people on this thread:

unable to bootup after Yosemite install. have to keep shutting down from rear button. it does come on after a few times …

My experience was very similar.

By any chance do you have McAfee Antivirus? Uninstalling McAfee resolved my issue.

The Macs that are having this issue don't have McAfee. We use ClamXAV for most of our Macs. Other Macs have Symantec Anti-Virus. The Macs were bound to our domain and had a software management system on them. I took these off and some Macs were doing a lot better, but a couple ran into the same issue. My boss ran a repair on the disk permissions on one Mac and seemed to be better. I'm not sure if this is the solution as things tend to come back. I'll post if anything is a solution, but as of right now it's just trial and error stage.

I had the same problem. And then after it booted I had a run away kernel_task.... The instructions here: http://forums.macrumors.com/showthread.php?t=1706948 fixed both problems.

This issue is different than yours, sallyRB. Everything was normal on my Activity Monitor and not overloaded CPU usage. Something is not right on OS X Yosemite. I had to restore my datas from Time Machine and 24 hours later my system got slow again so, had to clean install.

I don't trust anymore this OS X, cause anything could be happen soon. Yosemite is just disappointed and the worst OS X ever!

Just chiming in to say I too have experienced much longer boot times after installing Yosemite. I even went so far as to do a clean install on my computer that did absolutely nothing to resolve the issue. It normally takes about a minute for my computer to boot up.

Very slow, iMac Mid 2010. It takes 2-3 minutes to bootup. Switching users takes many minutes. Restarting is sometimes impossible or at least 10 minutes waiting is not enough before you give salvation via physical power button. Oh system is running from SSD via Firewire 800, same setup worked fine with 10.8 Mountain Lion. This is upgrade installation over Mountain Lion.

i think you should turn off the FileVault

I've done that but unfortunately found it to have no effect.

Hi Nirayer,

Would you be able to help me solve the problem I am also having with boot time? My mac takes around 3 minutes to start. I don't have any idea how to fix it. Thanks so much,

This helped some; took a full 60 seconds to boot before I did the steps, now boots in about 45 seconds. Still should take that long? Shut down is very fast, however.

So far it is over three hours and it has not completely loaded.

thanks a lot!