User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4a) Gecko/20030312 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4a) Gecko/20030312 When I try to download mozilla-win32-installer.exe the download manager shows a mozilla-win32-installer.exe.url file and at the end of download I get a dialog box with an error message that says: C:\DOCUME~1\MICO\IMPOST~1\TEMP\mozilla/win32/installer.exe.url could not be opened because an unknown error occurred. Sorry about that. Try saving to disk first and then opening the file. Reproducible: Always Steps to Reproduce: 1. visit http://ftp.mozilla.org/pub/mozilla/nightly/latest/ 2. click on mozilla-win32-installer.exe 3. Actual Results: The file is downloaded with the wrong extension and I am unable to find it Expected Results: Mozilla should have downloaded mozilla-win32-installer.exe Bypass: right click and download. Does not always work, for example when you have licence screens.

Duplicate of but 144334 or another one related ?

Delete the helper app entry you have for application/octet-stream, please. *** This bug has been marked as a duplicate of 189598 ***

Removing the handler for application/octet-stream solves the problem. Where does that helper application come from?