Why my file often corrupted if I download it with Firefox browser?
And it also stop automatically when the downlaod has not complete?
Depends - try another browser - if it works (no corruption) then I have no idea. If the file is corrupted on another browser, then try a different source.
Otherwise - no idea.
Kind of sounds like connectivity issues. You say sometimes the downlaod just stops. Other times complete downloads are corrupted... If the connection is breaking up or is unsteady in some way your downloads will and and some may get corrupted. I'd start with a connection verification.
-mwm
but if the connection stops you can still go on downloading. when you have your connection back.
you could try messing with the download settings in about:config, but if your not experience with modifying the values then i would just say try re-installing firefox.
it mite b becus of a dodgy internet connection
try the file on a different pc and browser, if its still coruppted, its prolly the web servers fault
it is a good idea to use a download manager especially for large files; u can pick up where u left off
also, check to see if the file is available P2P as most clients hav sum from of hash checking built in e.g. md5, checksum, etc.