Same as original poster but this Reply has an attach function. Pls see screen cap.

If you try to start Firefox in Safe Mode, does it work any better for you?

Thanks for the suggestion but I just tried it and it doesn't make any difference. Weird, since all was good until about a month or so ago. I don't even remember how many updates have occurred since then, but I can't think that anything else would affect an Options setting in the browser I use all the time.

Maybe Corrupt preferences file

see also:Preferences are not saved

thank you

Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

The temp location in "Local Settings" (environment variables %temp% and %tmp%) is used to initially store a download that is done in the background and is also used for files that are opened in an external program.

Some anti-virus software locks a file for inspection and prevents Firefox from moving the file from the temp folder to the destination folder.

Hmmm. I did swap out Spyware Doctor for MSE a while back because SD was killing my performance. I just now went to MSE and turned off "scan all downloads" and tried again. Same. I had planned to go thru the long effort suggested by ideato tomorrow, but I wanted to note that I don't have a problem changing the setting and having it remain changed. I can go out, reboot, whatever, and when I go back into Options, it has remained changed. Still, ideato has a lot of things for me to test, so maybe one of them will bear fruit. Before I do the testing tomorrow, I'll shut down MSE and re-enable SD to see if downloading goes back to normal (since I never had the problem before a month or so ago and I've had SD for a year). Thanks.