How to fix IE always opening Firefox instead

In: Browsers

19 Mar 2006

It was not until recently (when I had to actually open Internet Explorer to test some cross-browser stuff) that I realized my workstation and my home PC had a particular problem in Internet Explorer: anything I typed into Internet Explorer opened in Firefox (my default browser). After some Googling, a forum thread over at provided a solution – just delete the HKEY_CLASSES_ROOT\CLSID\ {c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6} registry entry.

Long version for Windows Registry newbies (alternatively, you can create a .reg file and run it like someone said in the thread):

  1. Click our Start button, then “Run…”.
  2. Type “regedit” into the box that appears and hit Enter. This will bring up the Registry Editor.
  3. Drill down the tree on the left pane under HKEY_CLASSES_ROOT until you find the HKEY_CLASSES_ROOT\CLSID\ {c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6} entry.
  4. Delete the entry.
  5. Close the Registry Editor – you’re done.

Anyway, turns out this is a bug caused by having “IE7 Beta1 in an unsupported side-by-side configuration with a version of IE6”, as officially stated in IEBlog.

Painfully, I had to look all over again for the solution back home because I didn’t bookmark the page and it didn’t make sense to run over to the office just for this. Now it’s bookmarked in and blogged so I won’t forget.

29 Responses to How to fix IE always opening Firefox instead



March 24th, 2006 at 5am

Woo! That’s been bugging the hell out of me for weeks.

Thanks for the fix!



April 1st, 2006 at 10am

Finally, a fix! Thanks alot!



April 21st, 2006 at 5pm

Weeeee, thanx, that was bugging me for days after i get rid of IE7



January 25th, 2007 at 1am

thank you thank you thank you. the only downside is now that I am available to fix IE problems in our software.



April 18th, 2007 at 7pm

I did that but no change. Any other ideas?


John Preston

June 9th, 2007 at 10am

Fantastic. I have wasted about 6 hours on this …

I had installed on XP SP2 IE7 (not a BETA) which had replaced IE6.

I found several serious problems that eventually forced me to uninstall (per the M$ KB article) – those problems were:

a) Word documents took around 20 seconds to display, even the simplest (no remote printers etc).
b) Excel did the same
c) .CHM files took about 7 minutes to display.

After uninstalling I still had a 5+ second delay from openening an empty ‘fred.html’ file on the desktop before IE6 even showed it’s menus etc.

Also I found I could not put the IE icon on the desktop via the ‘customize desktop’ option of display properties. That still doesn’t work, but who cares :-)

All this on a brand new Q6600 Quad with 4G ram and 2 x 750G eSata HDDs etc. Needless to say the machine was built with performance in mind, so these stupid delays were infuriating.

After uninstalling IE7 everything seemed fine, but as I hardly use IE, preferring Firefox, I only noticed the weird behaviour a week or so after uninstalling IE7. Attempting to resolve it, I uninstalled Firefox – then it still tried – just got an ‘application not found’. I also deleted the entire “C:\Program Files\Internet Explorer” directory, ditto for the HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER registry entries for IE. All to no avail. That incidentally also killed system restore and the management console :-(
I restored a copy from my laptop which had never had IE7 installed, and all the problems returned.

After considering blowing it all away and restoring a 6 week old backup (but that probably had IE7) or reinstalling IE7, I found this blog.

Fantastic and thanks.



June 19th, 2007 at 7am

Is there a reason why the Registry key would re-install itself? I’ve gone through the delete process three times already and I get the same behavior – it’s there again, and anything typed into IE opens a firefox window.

I wouldn’t care normally, but I need to test something in IE and this is a little frustrating.



July 29th, 2007 at 7am

Dan –

Been having exactly the same problem, which has driven me mad for 48 hours solid. I finally think I’ve cracked it. Look in C:\Program Files\Internet Explorer\ and see if there’s a file name ieproxy.dll. If so, right click, choose Properties and click the Version tab. Mine had a version number of 7.0 and then some. I removed it, and everything’s working normally again. I can only assume this is an IE7 file that didn’t get uninstalled. Try this at your own risk – I’m no expert in these matters, so keep the file in case things go haywire.

Incidentally, I never had 6 and 7 running side by side, but I did install the 7 beta and then the full version, then uninstalled it to revert to 6 (for compatibility with clients’ setups). That’s when all hell broke loose, with IE6 spawning a new window and hanging every time you tried to link to a different domain.

I stumbled on this solution when some judicious Googling led me to some sites about side-by-side running that mentioned the registry key HKEY_CLASSES_ROOT\Interface\{000214E5-0000-0000-C000-000000000046} in the same breath as the one above. It has a sub-key linking to the earlier file, and also refers to the ieproxy.dll file, which was what led me to it.



August 12th, 2007 at 5am

Interesting link – my prob has kind of been the opposite. I use American Greetings card site quite a bit and suddenly, my Firefox opening up a secondary window in I.E. isn’t working so I was hoping to force Firefox to only open Firefox secondary windows.



October 29th, 2007 at 10pm

Excellent information. It worked great. The reg key did come back repeatedly, but removing the ieproxy.dll file (which was a v7.something) stopped my reg key from reappearing. Many thanks!



November 28th, 2007 at 12am

hey that was an awesome fix.. it helped me resolve my customer’s issue




November 30th, 2007 at 9pm

Wow that was a crap bug , thanks for the solution.



February 3rd, 2008 at 6am

ah ha!!! Excellent work! Thanks for solving that crazy bug.



February 20th, 2008 at 5pm

Not sure if I’m the only one with this problem, but that registry entry doesn’t exist on my machine! I’m using the following:

WinXP SP2 German Edition
Firefox 1.5
IE 6
IE 7, not sure if Beta or not

The problem only occurs in IE6, and I’m running IE7 Standalone to acheive both versions. I installed yesterday, and it worked fine until just now. Anyone else encounter this?



February 20th, 2008 at 6pm

ok… the problem went away when I closed both IE7 and IE6 and re-opened them. I also wonder if the order in which I open IE6 and 7 matters, because with IE7 Standalone, a script is run in the background. I highly recommend that if you’d like to develop for both versions.




March 5th, 2008 at 9am

I have IE6 and IE7 installed in seperate directories for testing purposes. IE7 works fine along side FireFox, however IE6 was a problem.

For IE6 – after deleting the Registery Key it reappeared. The only ieproxy.dll was in the IE7 directory, so I tried removing this. This fixed my IE6 problem, but then IE7 would not run!

My current solution is to move the ieproxy.dll INTO the IE7 directory when I need to launch IE7, then move it OUT to launch IE6…

A pain in the butt, but it works… Any better solution, please let me know!



March 19th, 2008 at 5am

This is great!!!
Finaly my IE6 is back to normal.
Thank you very much.


Rich Chapman

March 20th, 2008 at 7am

RE: Posted by: Corvus on July 29, 2007 7am

Thank you so much! Fixed my issues, too.



March 28th, 2008 at 4am

I LOVE YOU. You saved my ars. I even installed ubuntu trying to make IE work there; man, I bookmarked this page into my permanent bookmarks (5 years and counting). And made a little note to it. if I BECOME RICH, you have a millon.

Take my damn word on it.

1 month looking for this. I should take a plane there and kiss you.



April 2nd, 2008 at 5pm

Wow – what a pain – I tried everything before I found this website – worked like a charm (after I finally realized I am supposed to delete the entire reg entry, not the entries within it) – thanks for the help!



April 2nd, 2008 at 5pm

OK, check that, this worked until I restarted Explorer and now the same problem has returned. I deleted the reg entry again (it had reappeared), but that didn’t fix it this time. Very irritating…


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Jigsha Desai

April 29th, 2008 at 3am

Thanks so much! I tried this and it worked. I had this issue for several months and your quick solution fixed it!

Thanks again!



May 6th, 2008 at 10pm

awesome! thanks –


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