Firefox, Vista, Outlook and URL General Failure errors

*UPDATE*Looks like after I spent all that time making this entry, that mozilla already had a knowledgebase article up about it. You can find it here:
So, in Vista with the latest Firefox update, I’ve noticed a problem when opening URLs in applications like Outlook or even the Windows Sidebar. I’ll get a popup like this:

Opening a link in Outlook makes it look like this:

Either way, the path to fixing it is the same. Open up regedit and go to the following registry key:
Double click on the Default string, which should have a value of “”%1″,,0,0,,,,”. Delete that value and leave it blank.

That’s it. You should not get the pop-up errors anymore. However, since this happened once, it will likely happen again. I believe it occurs when either Windows or Firefox (not sure which) resets the default browser on your computer to be Firefox. So next time that happens as part of a Firefox update or you messing with the Default Programs control panel, you may get the pop up errors again and have to redo this.
To make it easier you can just make a regedit file. Make a new text file, name it something like “FixFirefoxURLErrors.reg” and put the following into it:
Windows Registry Editor Version 5.00
Then just double click on the file and it’ll make the registry change for you.
Again, these steps are for Vista only. You may remember running into a similar error to this with Outlook and Firefox a long time ago, it seems to have come back. The steps one would follow on Windows XP don’t work on Vista, since Outlook is looking at a different registry key. All I’ve done out is which registry key that is (thank you Sysinternals Process Monitor program!) and applied the Windows XP fix seen here:
By the way, just a fair warning, you can do a lot of damage in the registry if you delete something you’re not supposed to, so be careful, I’m not going to help you if you break your computer. 🙂

18 thoughts on “Firefox, Vista, Outlook and URL General Failure errors”

  1. I have tried your suggestion, as well as the Mozilla additional steps. Now I dont get the pop ups, but the link still doesnt work.
    If, however, I set the default browser to IE, the links work. Of course, I hate IE, so hopefully you can help me get back to Firefox. thanks

  2. Unfortunately, the only recommendations I have are the KB article on mozilla. If that’s not helping, there isn’t anything else I can do, cause it fixed my problem and so I have no other errors to test with. Make sure you’ve tried restarting Outlook, Firefox, and windows of course.

  3. Non of the options that I found online worked for me!
    I have Vista Ultimate with Office 2007 and Firefox
    So, I tried following:
    1. Close all programs
    2. Uninstall Firefox through Control Panel -> Uninstall a program
    3. Delete Mozilla Firefox Folder from Computer -> C: drive -> Program Files
    4. Perform Disk Cleanup
    5. Restart Computer
    6. Download and Install new Mozilla Firefox from
    7. And it works 🙂
    It takes about 3-5 minutes to do all this and you are not playing with register keys risking to mess-up something serious!
    I hope this helps to some of you!

  4. Found this and it worked for my most recent Firefox update (3.6) on Windows 7 64-bit in Outlook 2007. From what I can tell so far, everything works like it used to. Thanks a lot!

  5. I agree that editing registry keys are highly risky and very complicated. So, unless you have got a backup of the whole system or the registry, don’t try to mess up with the system.

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