536916 - Firefox says that an incomplete partial download was completed successfully

Status: RESOLVED DUPLICATE of bug 237623

(Firefox :: General, defect)

Description

[Victor]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; pt-BR; rv:1.9) Gecko/2008052906 Firefox/3.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; pt-BR; rv:1.9) Gecko/2008052906 Firefox/3.0

Sometimes, when downloading very large files (possibly with a slow connection), the download is interrupted by whatever reason and firefox says that it was completed. However the file is incomplete and this makes it frequently useless.

Reproducible: Sometimes

Steps to Reproduce:
Download a large file somewhere. I tested with this: http://downloads.sourceforge.net/project/inkscape/inkscape/0.47/Inkscape-0.47-3.exe?use_mirror=ufpr

Keep the download running and keep an eye in the progress bar. If you are (un)lucky enough, you may see it skip directly to end. Firefox will say that the download is complete, but it is not. This is really very bad and annoying to the user, because he/she may be fooled that everything is ok if not keeping an eye in the download.
Actual Results:  
I tried three times to download it. The file has 37 Mb. The first trial downloaded 7.9 Mb and was interrupted. The second downloaded 7.5 Mb. The third downloaded 1.7 Mb. In all the cases, the downloaded file was incomplete and useless.

Expected Results:  
I expected that the download was really completed successfully or at least that firefox did not lied and told me that it was not.

I already saw somewhere that this occurs because firefox sometimes does not really know the download size and sometimes the expected size is wrong. I think that it would be reasonably to warn the user with something like this: "downloaded finished but possibly incomplete, because the downloaded file is shorter than the expected size".

Comment 1

[Ionut Negru]

Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 (.NET CLR 3.5.30729)

I had the same behavior on 3.5 and now on 3.6.3 however it happens also with fast connections.

Another aspect that I should add is that all the times I have encountered this behavior I had multiple downloads running and when this happened they all got advertised as complete although they weren't.

Comment 2

[zowki]

I too have the same behavior on Firefox 3.6.3 too across Windows and Linux operating systems. I am very frustrated by this because it has been happening to me for years.

Similar bug reports here:
https://bugzilla.mozilla.org/show_bug.cgi?id=493534
https://bugzilla.mozilla.org/show_bug.cgi?id=546670
https://bugzilla.mozilla.org/show_bug.cgi?id=476503

Perhaps these other bug reports can be merged?

Comment 3

[samsmas10]

Me too, FF 3.6.6 on Windows 7 x86-64.

Comment 4

[mcha226]

I am using wireless network, and this does happen to me from time to time, even on small files. I am wondering if Firefox actually uses HTTP response header to verify the file size being correct or not.

Comment 5

[Peter da Silva]

This bug is 8 years old. The best advice given is to install a download manager extension. Please give it some love.

https://bugzilla.mozilla.org/show_bug.cgi?id=237623

Comment 6

[jaysee5]

The bug lives on in Firefox 32.0.1 Windows 7

Will this ever be fixed?