Login window disabled/disappears after software update

Hello Arne

You say you ran Disk Utility. Did you do Repair Disk?
Did it report any errors?

The good news is your disk seems alright, and it may only be a few corrupt preference files that need deleting.
Unfortunalety you may have to do this from the command line, unless you have another Mac to use where you can use access your troublesome HD from another computer. Though at this stage we can't be sure what is exactly at fault.

Have a look at this topic Stuck at 'Login Window Starting' read what Rich JG posts about removing some .plist files when booted from single user mode using the console. (reference is provided below)

The actual fix was done using Firewire Target Disk mode as the poster had another Mac to get some files off, and if you do that could be one solution, otherwise, go with the Apple Discussions article suggestion No. 5, provided here:
http://docs.info.apple.com/article.html?artnum=106464
and delete these files as described.
com.apple.loginwindow.plist
com.apple.windowserver.plist

You have a bit of work to do. I hope it goes well for you.

Hey I can do you one better.
After doing some clean up on my iMac I ame across a chunk of memory (40gigs) in the form of a "sparse file" unmounted.
I used utility program and first aid on my existing hard disk and it came up with minor fixes . I then tried to run first aid (verify , etc.) on tghis sparse.disc or file ??? and it imediately came up with a pop up that warned that if I tried to open it it could damage my computer. What the ****...I click open and it imediately quit the diognostic and gave a dialogue box that said it was unmountable. I then returned to using my computer a bit and sshut it down for the night.
I just fired it up and got a very strange and un Mac like start up screen:
gray background with a gold tinted square in the middle of the screen with a full color world icon centered in it! No log on blanks nothing ! It was kind of a poorly rendered icon and the whole screen was static.
I clicked on it ..nothing...I was thinking "Oh SH*T...it's a doomsday virus of some sort!" I imediately went unconsiously into APPLE mode (and that's not ala any pie!) switched off the iMac from the back and then depressing the start up button I held it and instintively also held down the option and cap lock keys (I really don't no why?) and the iMac rebooted to a root line system level where it told me to type in I think mac-boot and I did. The iMac shut down and came back up normally and I am now here and asking ....
What is up with my MAC!?
What is the FIX for both the start up and is it related to the "sparse thingy"
I played with the night before? And if the sparse thingy is 40 gigs how can I break it up to off load it onto some DVD RW's or is it bite the bullet and erase it...I know I have missing files that I can't find and I suspect this is where they are. If you click on my icon you will see on and around May I reported that one moring all the files that I had on my desktop disapeared and that is around when I noticed these other files also couldn't be found through a finder search. Is this a virus at work ?

Hello Again t-art!

Relax, it's not a virus.

But as you never responded to My reply, in your other Topic walking blues posted on May 1, perhaps it would help if you did so now.

ali b