In some cases, when a large file had been downloaded through Mozilla Firefox, downloading of file gets interrupted for some reason. The Firefox would tag the download as “failed” and you are left with nothing but a .PART file. You right click it, it would ask you to ‘retry’ which would restart the download from the beginning. In my case i had been downloading a 100MB zip file and it failed once 97MB of it was downloaded.
Fortunately, we have a workaround for resuming the failed download. After the download failed, there should be two files in the download/destination folder. One with original name of the file and another with an extra “.PART” extension. If you have just .PART file there and not the original file, just copy the .PART file and rename it to the same name of original file – by removing .PART extension of it. Now you should have two files there in any case, one with the original name and one with an extra “.PART” extension. Let’s move on.
1 – Move both files to a new location (only cut / paste and no copy – if you copied, just delete source files).
2- Start download again from the beginning.
3- Let it download a few bytes, just to have those two files created again, with the exact same name. Now PAUSE this download.
4- Go to the folder where files were backed up. Copy both of these files to download folder and replace the new created files when asked.
5- Now go to Firefox’s Downloads window and resume the download.
It worked for me and it should work for any as well (Thanks to orion188 for posting at http://forums.mozillazine.org/viewtopic.php?p=3069821&highlight=).