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.

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.
You can export key(s) before making changes.

Try to 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

Hi,

Thanks for the reply but so far no fix in safe mode!

John

Hi,

Thanks for your help.

Currently also I'm running Sfc/scannow but it is taking forever.

When you say "Delete the subkeys (LastVisitedMRU and OpenSaveMRU) " do you mean whats in those 2 folders, not the folders themselves?

+ I'm not sure what any of this meant.......... "Try to 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" 

Cheers, John

PS I wanted to add an image but of course I can't can I.

You can either delete those two folders or only the key it.
Windows will create a new MRU key when those are missing and removing the keys is easier then clearing up a long list.
A lot of keys can get cluttered there over time.

Did you already try to remove the mimeTypes.rdf file?

The mimeTypes.rdf file stores file actions that you see in Tools > Options > Applications and it is possible that there is some interference.

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

You can also check the download prefs on the about:config page in case some point to a location that no longer is available.

• http://kb.mozillazine.org/about:config

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder

Well after running Sfc/scannow which took some hours to run the issue now seems to be resolved, and so my apologies for thinking it was Firefox!

Cheers, John

Thanks for reporting your findings.

And thanks for your help, most appreciated!

Cheers, John