Screen Junk on log in and shutdown - sometimes

I too have just had the same screen appear on my computer right after the latest update to 10.5.5 and the latest security update. This really concerns me as I use this computer for editing dvds for kids for college recruitment and need to make sure their products will not be affected. If there is a solution for this could somebody post it quickly or can apple quickly put up a working patch that will take care of this. I have also notice that the speed of my dual G5 with 8 gigs of Ram is slower after that last update.
This is the first time in 15 years of buying macs that I have had any adverse affect from an update!
Sue

I had exactly the same problem/same system and just spoke with AppleCare, who resolved it. The problem was caused by a corrupted desktop preferences file ("com.apple.desktop.plist"). Apparently a very rare occurrence.

To get rid of the corrupted plist file: Open your hard drive icon, open the Users folder, open the "Home" folder (your account's folder), open the Library folder, open the Preferences folder, and then find the "com.apple.desktop.plist" file and move it to your desktop. Restart your machine, log-in, and hopefully your problem is gone. When you login, your desktop pic will have been replaced by the default "Aurora" picture. You can then trash the plist file you moved to your desktop.

I am having the same problem. It started just after the last update.

I have the same problem - just started a couple of days ago - iMac isn't a month old - any fix yet?

Thanks for the tip. Didn't know there was a Security Update. Just downloaded it. Will know in a couple of days whether it worked.

I am also experiencing these same problems, but it occours every time I log in and shutdown! I cannot believe that Apple haven't addressed this issue yet especially when it's probably related to the recent OS update. I need to know wether this is a hardware or software issue or both, before my warranty expires in November! Another experienced Mac user, using the same machine as me has had no problems with his, but he recommended that I checked out the RAM! Has anybody found an answer to this annoying bug! I tried deleting the desktop plist file which has been suggested within the forums, but this does not work! Help!

Just downloaded and installed the new security update and it seems to have fixed this issue! Weird!

Yeah, problem is back again! Very annoying. Anybody know if there is an official statment from Apple concerning this issue yet!

Went through Apple Care on this same exact problem. Deleted various plist, like suggested. While no solution was arrived at I was able to boot in SAFE mode without issue. Seems User Account related but not a startup item or plist file ...at least none I've deleted. My added dilemma is that my iMac is also freezing every third or fourth shutdown. I'm thinking about doing an "archive and restore" of my OS.

yes. thanks for starting this thread and uploading the screenshot. I have the same exact problem. And same window wiping to clear screen.

It seems to occur most often when switching between user accounts. (fast user switching)

I didn't know how to describe it, or what to look for in discussions. "screen junk", as you said, is probably as good a term as any.

I think it is important that all discussions on this issue be cross-linked. If you know any other threads discussing the issue, please provide the link.

Other descriptions might include terms such as: crazy screen desktop patterns noise mess graphics cards monitor drivers log-in

Hi there everyone ....I am also getting this problem and like someone else in here am desperate to know if its hardware or software issue as I have a warranty running out shortly. I have also been experiencing other issues that have been fixed after downloads and then after a little while the problems are re occuring ....it sometimes takes my mac over 20 mins to boot and then sometimes its with me within minutes, all depends on the weather from what I can make out!!! sometimes it runs really fast and other times I feel like I want to chuck it out the window cause its so slow, then to top it all I have this funny kind of fabric background on my desk top that does disappear if I open or move windows.

So how do we find out if Apple have addressed this problem now we all know it exists? any help would be much appreciated as I have just uploaded all my little girls baby videos to put onto disk and don't want to loose them off my system before reinstalling my software etc

Bizarre graphics incident 2 times this month on four month old iMac:
http://www.curwen.org/images/iMac3.06w.jpg

Each occurred at wake from sleep at normal room temps, etc.

Top pix (Oct 9) had large and random geometric shapes and included unusual cursor behavior wherein cursor left behind a series of thumbnails of a portion of desktop. Movement erratic and ceased altogether. Reboot removed issue.
Bottom pix (Oct 11), has my cursor looking unusual and a section of my dock missing. Reboot removed issue

Per MacFixit, I have reinstalled 10.5.5 combo updater in attempt to address possible driver corruption. Safe boots and LCC runs, also. So far, so good (Oct 15)