When I upgraded to FF 26, I found that I can't download .exe files.I had some trouble like this with FF25, so I changed the "scanWhenDone" property to false; it helped with FF25 (my downloads completed), but now I start a download, and I don't even get the "save or open" box, and FF26 shows no sign a download even took place. I also went into Control Panel and reset the security levels to their default values, but that didn't help either.Can you some suggestions for other things I could try? Many thanks,
Installing comodo in the basic mode probably solved the problem for you.
However, be aware, that it is generally not supported to do so, if you do not have any other HIPS programs running that prevent you from malware and leaks.