I downloaded a 690MB iso image using kget in kde-suse and after I got the "All downloads completed" popup I went to burn the image but it wasn't there.
I had downloaded it to my /home/user/downloads folder and about 5 minutes before it completed I noticed the iso.part file was there, along with the md5 file for the iso I had download a bit before.
Now the md5 file is still there but no iso or iso.part.
I did updatedb and have tried using locate and doing a full file search and there is no sign of this iso.
I have looked in the kget log and there were no errors, it downloaded the whole file without needing any retries and at the end of the log it says the download was completed.
I've also checked the permissions on my home folder to make sure write access is ok and it is.
I have used kget many, many times in suse and other distros and have never had this happen before.
I haven't done any upgrades to kget or anything else in suse for over a month so it's not a case of it being new and buggy.
To make things worse, I had been trying to download the iso for 4 days but couldn't find a decent mirror, the average speed was less than 1 kb/s on a 2 meg connection.
So I finally found a faster mirror (though still not full speed) and now this happens.

Is it possible the filename began with a '.'? If so, it may be hidden. You might try 'ls -a' on the dir you tried to d/l the iso to. That's the only thing I can really think of.

No, it was a regular filename and ls -a still didn't show anything. I thought it might be at least in a temp directory somewhere but it's has completely vanished off the face of the earth.

Pretty strange. Try taking a look at kget's log: (In kget) View--> Show Log Window. Hopefully it still has some clues as to what happened.

According to the log it was downloaded to the directory I had mentioned and completed successfully. There were no errors or anything whatsoever that would indicate a problem.

Hmm, my last idea is that it could be a quota problem. Unfortunately I know little to nothing about quotas in Linux, having never used them myself. I would think that kget would show that kind of error, though, unless I overestimate kde's developers.

I think this is beyond my admittedly limited expertise. Good luck.