Yosemite desktop blinking, menubar not appearing, fan 100%

[jewfromdahood]

So I tried installing 10.10 via Update, fresh install from it's own flash drive and everything but nothing seems to work as I get the SAME EXACT PROBLEM
I tried this site here http://www.macambulance.co.uk/mac-os-finder-stuck-crash-loop/ that didn't work, I tried the solution of changing Dashboard from Overlay to Off. Nothing seems to work... It goes to 100% fan (which it never has done before) desktop keeps blinking, the apple logo in the corner disappears and has a black bar run the entire screen down. I have never ever had this issue, I can't even reboot I have to do a hard reboot pressing and holding the power button. I have had to reinstall OS X with the Mavericks Flash drive I still have with 10.9.5 as 10.10 doesn't seem to work AT ALL... To be completely honest it feels to me as if Apple didn't do enough testing for everything on it. I don't have third party apps other than a Fan control app, and DNScrypt which should not affect it in this way in the least...
I had to reload Mavericks until I finish with work as I need a working Mac for tomorrow. Highly dissapointed with OS X 10.10 never had an issue with OS X on this early 2011 Macbook Pro with a Core i5, 16GB of RAM, that ran smoothly from 10.6 all the way through 10.9.5 until now... Thank god for time machine

 

[john2188]

Yosemite Flashing Desktop with Missing Dock

As a last resort, I followed a suggestion that I thought was a bit frivolous. I was desperately trying to get my 2009 MacBook ready for my Granddaughter's birthday. It goes like this - I had only one account, an Administrative Account in Yosemite. I added a Standard Account and voila the desktop picture was no longer flashing.
Now assuming that you have a lot of data in the Admin Acct you have been using, simply make a new Std Acct an Adm Acct and convert the original Adm Acct to a Std Acct.
How do you do that? System Preferences>Users & Groups>unlock the Padlock by clicking on it and providing your user name and password>click on Log In Options>select the user account you wish to change if you have more than one account>check or uncheck Allow User to Administer this Computer.
If you have only one account, click on the Lock and enter your user name and password>click on the + symbol in the lower left hand corner of the left pane>set up the new User Account with user name (probably should be different) and password (which can be the same) and check or uncheck whether you wish for the account user to be an administrator. And, if you are as fortunate as I was by selecting the non-user account (the user account desktop is still was flashing), you won't have a flashing screen in the Standard Account. Installing software or making various changes in the Standard Account will require your Admin Acct. user name and password, but you don't have to Log Out and Log back In to the Admin Acct or Shut Down and Reboot.
A fringe benefit of running a Standard Account is that it is immune to a recently revealed vulnerability in Yosemite to hackers!