Normally, Firefox never opens an IE window unless there is a particular kind of download that is set to open in IE. But this could be a side effect of an add-on.

Could you test in Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Safe mode does not automatically disable plugins. If you want to rule those out as well, you can set the ones that don't seem critical to "Never Activate" here:

orange Firefox button (or Tools menu) > Add-ons > Plugins category

That made it much worse. To be able to get to this page, instead of clicking on the link, I had to right-click in Eudora, Send to Browser. That indicates that Eudora is correctly linking to the FireFox default browser, and that tehre is no logical reason, why clicking on a link should open IE with a bare-bones version going to about:blank I can figure out most problems, but this just does not make sense to me. Hopefully you can figure it out! Thanks DearWebby

I misunderstood your original question. The links that cause the problem are in the stand-alone Eudora application, and not in a page already open in Firefox?

Sometimes it helps to refresh the default browser setting by having IE make itself the default browser, and then having Firefox make itself the default browser again.

No difference FireFox is the default, manually put into the registry, and has opened from Eudora for many years. It still does, but it also opens the nuisance IE windows. When researching something I often wind up with a dozen nuisance IE windows open. When clicking on the link to your answer, it opened the proper page in FireFox and also IE: about:blank#answer-505360

This problem started with the goofy FF version 21 All versions of FF up to that did not have the about:blank problem. Have FUN! DearWebby

Hi DearWebby, you wrote:

When researching something I often wind up with a dozen nuisance IE windows open.

What are the steps you are taking when researching something -- is this just browsing in Firefox normally?

I wonder whether some kind of web content is set to open in IE rather than Firefox in your download preferences (Options > Applications). I can't think of an efficient way to search for that, and since that file occasionally becomes corrupted, the dialog may not tell the full story.

The customary remedy is to rename the file and allow Firefox to rebuild it based on your active plugins. Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using

Help > Troubleshooting Information > "Show Folder" button

Switch back to Firefox and Exit

Pause while Firefox finishes its cleanup, then rename mimeTypes.rdf to something like mimeTypes.old

Restart Firefox. You'll probably need to update a few preferences (e.g., preferred PDF viewer if it's not the built in one), but hopefully whatever Firefox has been handing off to IE will now be handled internally.

Any luck?

You can check for problems with DDE.

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

Researching just via regular html. Typical example: I write the DearWebby Humor Letter, ( http://webby.com/humor ), which includes the "International Bonehead Of The Day Award", listing some dumb crook and his/her crime. Quite often i get a lead without a mug shot. So I have to search online newspapers until I find one, that has a mug shot of the crook. Nothing exotic, just regular HTML.

The same happens when I clicked on the link to reply to you. It opened this page, but it ALSO opened a nuisance IE about:blank page with about:blank#answer-505566 in the address bar.

I have used FireFox since version 1.2. This nuisance started with FireFox version 21, or maybe 22. It usually does open a Firefox window with the correct URL, but does not bring it forward.

It simply does not make sense to me.

Thanks! DearWebby

Let me know whether you notice any changes after renaming the mimeTypes.rdf file.

Regarding links opening in new windows, if they start to open in front but then the window where you clicked comes back in front, that could be a bug in the protected mode of the Flash Player plugin. Please see this thread for further details and known workarounds: Opening New Windows and Shockwave Flash.

Here is what actually happens, for example, when I click on your link in the email to get to here. The email program, Eudora, occupies 2/3 of the right screen Showing through past the edges of Eudora is Excel, and past the edges of that is one FireFox window with regular HTML stuff, like invoices. On the left monitor are a few SSH2 windows to servers and Skype, and another FireFox window with AccuRadio, running but minimized. Sounds confusing, but isn't to me. I have operated like that for over a dozen years.

Now, when i hit the link in your email, le left screen pops a nuisance IE window with about:blank#answer-505667 On the right screen, where I am, where FireFox used to come to the front until version 21 or so, I have to find an edge of it and bring it forward. Once I got it in front it starts going to https://support.mozilla.org/en-US/questions/978700

Mime types are not involved, as far as i can see. I will read up on that potential Flash interference. AccuRadio.com in the other FF browser does use Flash. Thanks DearWebby

Did you at least try to rename the mimeTypes.rdf file temporarily to see if it has effect?

Let me see whether I can summarize this welter of odd behaviors:

(1) Clicking Links in External Applications

Expected behavior: link opens only in default browser and Windows gives that window focus.

Actual behavior:

(A) Firefox already running in normal mode: IE opens a window to about:blank, Firefox receives the URL but does not start loading the page until you manually bring the Firefox window forward. (I assume you are using the default setting of the external link opening as a new tab in the last active Firefox window.)

(B) Firefox already running in Safe Mode: IE opens a window to about:blank, Firefox does nothing at all.

(2) Using Firefox Normally

Expected behavior: Firefox handles all standard HTML documents and inline media, diverts documents and media it cannot display to helper applications.

Actual behavior: IE windows open in the background while browsing in Firefox.

Is there anything special about the way you start Firefox, e.g., using a command-line switch or sandboxing software?

Renamed mimeTypes.rdf to 1mimeTypes.rdf restart FF in safe mode, then exit that to normal mode. Theoretically, that should have unloaded the mime types, but those were all standard anyway. No change. Colorful Tabs updated, so it must have been a proper reset.

No special way of starting FF. And clicking on a link does properly open a new tab, but without bringing FF to the front. I am still running now with mimeTypes.rdf renamed to 1mimeTypes.rdf Have not noticed any changes in anything.

You mentioned something about editing a registry setting manually, but I can't tell whether you refreshed the settings by doing the "double switch" of the default browser.

That was many years ago. To make Windows 7 recognize Eudora as the default email program, you have to edit the registry. That is for the opposite direction, to go from any program TO email. That has worked fine for probably 10 years. That has nothing to do with Firefox.

The problem is that since version 21 of FireFox, when it is called from an email, it accepts the URL, but then calls IE and opens IE in front of it.

I tried it with FF open alone on monitor 1, and clicking on your link in email on the other monitor. That causes FF to open a new tab with https://support.mozilla.org/en-US/questions/978700#question-reply, then opens IE in front of it, with about:blank#answer-505794 and covering FireFox. It is not a fatal error, just a nuisance.

Okay, assuming you have not tried it yet, please try the double-switch of your default browser. This will not affect your default email client.

Yes, I know, the default email client is fro going in the opposite direction. That is a Windows default and has nothing to do with FireFox. I DID close FireFox with the Windows Task Manager, re-opened it and had a FF winwow open on monitor #1, then clicked on your link in the email on monitor #2 Here is what happened: 1) FireFox opened a tab with https://support.mozilla.org/en-US/questions/978700 2) then a second later called IE and opened it IN FRONT OF FireFox, with URL about:blank#answer-505877 covering up FireFox. It did not close FF, just trumped it, covered it up.

What are you saying. What I suggested did not work, or you are just replicating the problem over and over and not trying my suggestion?

As mentioned above, I did rename mimeTypes.rdf to 1mimeTypes.rdf, reset to safe mode and tested, reset to normal and tested closed FF with the Windows task manager opened FF normally and tested

And I am still running with mimeTypes.rdf renamed to 1mimeTypes.rdf

No change whatsoever as far as the call from FF to IE is concerned. That call now is definitely one second AFTER FF opens a new tab.

The default browser "double switch" is having IE make itself the default browser, and then having Firefox make itself the default browser again.

• http://windows.microsoft.com/en-us/in.../make-ie-default-browser

• Make Firefox your default browser

The topic title is misleading. As described, I have since found out that the email program does call the default browser, FireFox. A second after Firefox opens a tab with the required and correct URL, Firefox calls IE with incomplete information. It gives the page title to IE, but not the URL.

FireFox IS the default browser and has been since version 1.2. The email program DOES call FireFox. It is FireFox, that then calls IE.