Applications just close?

Question

One of my co-workers has just started experiencing an issue where all of his applications just close out for no reason, with no error message. He is then brought right back to Finder.
Apps running so far have been:
iTunes
Safari
Quark 6
Quark 7
various CS3 products
This just started happening the other day, and it has happened w/a mix of those programs running at various times. He is still running 10.5.2, as 10.5.3 was causing other issues w/Adobe products, and we haven't moved up to 10.5.4 as were waiting to see if there are any other issues caused w/Adobe apps.
Any ideas on what could be going on?

Answer 1

At the very least s/he should have gotten the generic your program quit - cancel, relaunch, send info to Apple - dialog box. And don't forget the crash logs - even mere mortals kind sometimes find hints in there. Seeing the list of applications I note that they all have high memory footprints so I'd immediately start looking at memory usage, empty hard drive space, and hard drive health.
The memory usage is self explanatory, I think. With these programs (especially if more than one is going to be run at a time) the computer should have a minimum of 2GB and I'd prefer 3GB. As I'm sure you know, if you launch another program and your computer doesn't have enough physical memory for it, RAM data will be written to the hard drive to free up enough space. Your hard drive needs to have enough free memory for virtual memory to work efficiently and if the hard drive is getting close to full virtual memory begins having problems. And finally, if the hard drive needs repair (not physical but file repair via Disk Utility) virtual memory can also have issues. And then there is the possibility of physical drive issues so when you open up Disk Utility check out the S.M.A.R.T. status of the drive.
The issue might be totally unrelated but it would be worth checking out that the computer's hard drive isn't more than 90% full or has at least 10GB free. This is my standard recommendation for a healthy computer. Run Disk Utility and repair the drive if necessary. If the computer has only 1 or 2GB of RAM consider upgrading it if possible. Throw away Quark - okay, I'm showing a serious bias here but Q6 just fried my tuchus from here to next week more than I want to think about. I can't get the university communications department to move to InDesign but they have nothing but trouble with Q and expect me to drop everything to help them out.
Before I write a book here, I'll also mention the standard diagnostic tool - a new user account. If the crashes don't follow into the new account you know there's something going on with the account & not the computer.