Try the Firefox Safe Mode to see how it works there. The Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open the Firefox 4.0+ Safe Mode by holding the Shift key when you use the Firefox desktop or Start menu shortcut.
• Or use the Help menu item and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Don't select anything right now, just use "'Start in Safe Mode" To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shift key) to open it again. If it is good in the Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one.

Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Early on I tried starting firefox in safe mode as one possible fix, and that didn't solve the problem. I just tried again right now with the fresh installation, and still no luck.

Any other ideas?

It is possible that your anti-virus software is corrupting the downloaded files or otherwise interfering with downloading files.
Try to disable the real-time (live) scanning of files in your anti-virus software temporarily to see if that makes downloading work.

See:

• http://kb.mozillazine.org/Unable_to_save_or_download_files

Thanks for the suggestion, but I had tried disabling my AV real-time scan, as well as setting browser.download.manager.scanWhenDone to false, and neither addressed the problem. I also tried this just now on a freshly installed firefox, and still no luck.

Any other ideas (that are not spelled out on the "Unable_to_save_or_download_files" page, all of which I've tried? Thanks in advance.

You may still be have some security software that is causing problems and you may only have disabled the user interface and not the services that run in the background.

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

Thanks for the quick response. I had earlier tried running firefox from within Windows safe mode as well, and I tried it again just now - I'm still having the same problem with firefox hanging when attempting to download files. I even tried starting firefox in safe mode after booting up in Windows safe mode, and still no luck. And that was after I uninstalled my anti-virus software and then reinstalled it (not that this would likely be a factor in safe mode, but I'm running out of ideas). Again, I don't have file saving issues in IE and Chrome, so this is a very curious problem. Any further directions to explore would be appreciated. I'm using Chrome as my default browser, but would prefer firefox.

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

That was the first thing I tried, and it did not work. Please understand that I completely uninstalled firefox, deleted all files and folders associated with firefox, and then reinstalled firefox afresh, and even that did not solve the problem.

Does this happen with the file picker window open (where to save the file) or already with the Open with dialog to specify what to do?

As soon as I position the cursor on a link and right-click, and select "save link as...", firefox freezes. I don't get beyond that point. It doesn't matter whether I select saved files to download automatically to my download folder, or to a folder of my choosing - the freezing still occurs.

Delete the mimeTypes.rdf file in the Firefox Profile Folder to reset all file actions.

• http://kb.mozillazine.org/mimeTypes.rdf
• http://kb.mozillazine.org/File_types_and_download_actions#Resetting_download_actions

Deleting mimeTypes.rdf and then restarting firefox unfortunately didn't stop the freezing. The default actions for individual file types works fine as before (e.g., acroread opens by default for pdf files, windows media player opens when selecting a .wmv file, etc.), but specifically when trying to save a file is where I get into trouble.

It may or may not be relevant, but when firefox freezes the cursor is an hourglass, so it's in the midst of performing an action (saving, apparently) on which it hangs.

Try to delete the MRU (Most Recently Used) ComDlg32 registry keys with the regedit.exe program.
Navigate to: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\ComDlg32
Delete the subkeys (LastVisitedMRU and OpenSaveMRU)
Be careful with editing the registry as there is no Undo possible: all changes are applied immediately.

• http://www.winxptutor.com/clearmru.htm

I deleted those subkeys via regedit, rebooted my machine, and tried saving a linked pdf file after opening firefox, and it still hangs. My gut feeling, though, is that the problem may be related to a corrupt registry entry as in your most recent suggestion, or a corrupt dll.

By the way, and as I mentioned previously, when I try the same process on Chrome or Internet Explorer, and I do get a pop-up window asking for the folder in which to save the linked file. I wonder if there is a registry key (or keys) involved in the problem specific to firefox but not chrome or IE.

Try to delete the content-prefs.sqlite file in the Profile Folder.

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

You can also try to reset Firefox:

• https://support.mozilla.org/kb/Basic+Troubleshooting

No, same problem. I tried that previously, following the posted instructions for what to do when having issues saving files. With a fresh installation, it's difficult for me to believe this would have been the source of the problem.

I have exactly the same problem since this morning, except that it's on Linux, meaning that the problem is not with Windows registry.

Another detail: my Firefox setting are such that it asks me whether I want to open the file or save it. When I download a PDF, for example, it opens in Adobe Acrobat and Firefox only freezes when I save the file from Acrobat. The file actually gets saved! Hence, the problem is probably related to copying (moving?) the file from the temporary location.

I see that the thread stops on 12/27/12 -- did you find a solution?

I still haven't found a solution, unfortunately. That's helpful to know that the problem is not specific to Windows. However, given that I completely uninstalled firefox and reinstalled it and that the issue hasn't gone away, it's even that much more curious.

The situation you describe is identical to mine. When a pdf file opens in acrobat, I can save the file within acrobat.

Another detail at my end is that I cannot upload files (in addition to the inability to directly download), e.g., through a form page that requests uploading a document. I have no problems with other browsers on the same machine.