I don't know about the error message you got but that is not the way to start a different version of Firefox -- include the pathname. And if you are trying to share a profile that is bad also as you could damage a profile, though Mozilla does try to avoid damaging, you should not mix the production version profile with one of a beta unless you are looking to create/solve additional problems for those that inadvertently do that. What does the UX stand for after 10.a1

Some links without reviewing them on my part test using multiple profiles. See links at bottom as well like command arguments

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

Some more:

• http://dmcritchie.mvps.org/windows-7/win7.htm
• http://dmcritchie.mvps.org/icons/win7_quicklaunch_large.png
• http://dmcritchie.mvps.org/firefox/quicklaunch.htm
• http://dmcritchie.mvps.org/firefox/firefox.htm#launchy_notes
• http://dmcritchie.mvps.org/firefox/firefox.htm#launchy

Google: Firefox The procedure entry point NS_SetDllDirectory could not be located in the dynamic link library xul.dll

http://www.google.com/search?complete=0&as_qdr=all&num=100&hl=en&q=Firefox+The+procedure+entry+point+NS_SetDllDirectory+could+not+be+located+in+the+dynamic+link+library+xul.dll&btnG=Google%20Search&sourceid=Mozilla-search

I'm not sharing a profile between two different versions of firefox. When I type "firefox.exe" into the run box, it launches a different version. I want to know how to make the UX version default. (Note that I have a separate profile for the stable release, if UX ever breaks.)

I've run nightly builds since 4.0a1, and have never experienced this problem. Also, UX stands for User eXperience. The UX branch gets more User Interface patches before Mozilla Central.

Once I get on my PC, I will look at your suggestion, and let you know if it solved it!

Your suggestions didn't help. For now, I can type "C:\Program Files (x86)\ux\firefox.exe" -safe-mode into the run box, but I would like to type firefox.exe -safe-mode into the search box, without it running "C:\Program Files (x86)\Minefield" -safe-mode

My question is: How do I change the default firefox.exe to point to C:\Program Files (x86)\ux\firefox.exe ?

-> Use Win + R key combination and enter the following in the Windows Run box:

• "C:\Program Files (x86)\ux\firefox.exe"

-> When Firefox starts, check which version its opening. IF its the UX version, then do the following:

• click Firefox button and click Options (OR File Menu -> Options)
• Advanced panel -> General tab -> place Checkmark on Always check to see if Firefox is the default browser on startup -> click Check Now button and make it the Default browser
• click OK on Options window
• Close Firefox

-> Again use Win + R key combination and this time enter the following in the Windows Run box:

• firefox.exe

Check which version its opening now.

@mha007 I tried your steps, but it didn't help. I think I'm just going to type the full path into the run box, but I will leave this question unsolved in case anyone finds the answer.

Try to ask in this mozillaZine thread:
UX Branch Discussion • mozillaZine Forums: http://forums.mozillazine.org/viewtopic.php?f=23&t=2230295

I talked to the mozillaZine people. I decided to use a new thread on the Firefox Builds board instead of the UX Branch Discussion thread, simply because questions could easily get lost in the UX thread, and my question could be applied to all builds of Firefox.

Anyways, it appears that the most recently installed version of Firefox takes the registry entry for firefox.exe, so an uninstall and reinstall of UX did the trick!

Thanks everyone!