User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.3a1pre) Gecko/20090915 Minefield/3.7a1pre Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.3a1pre) Gecko/20090915 Minefield/3.7a1pre I think there must be a bug in command line arguments taking effect. Because I've been trying to test directly like bug 471997 comment 49 I got the same results over and over again, didn't wfm, about:privatebrowsing asks if I want to start private browsing, everything looks the same as normal mode, with latest nightly trunk. I just started testing -private. no PB mode, didn't wfm. So then I decided to see if -P worked, no profilemanager, didn't wfm. hmm. Then I went back to -private it worked and always works now. double hmm. Then I tried -profilemanager, the profilemanager popped up. ok, works. Then I tried -profilemanager -private, ok, works. Then I tried -p, got the profilemanager Then I tried -P, got the profilemanager Reproducible: Sometimes Steps to Reproduce: STR seems based on whether the profilemanager has been used. Actual Results: Seems if you never used the feature it doesn't become active until the profilemanager gets used. Expected Results: upon downloading a new build, command line argument should be recognized and take effect immediately with current profile.. I was tried to verify bug 471997 and ran into this.

Is it possible that you had another instance of Firefox open when you tried the above?

I did try that case, but I made sure I was checking to see if Firefox was shutting down, which the process window didn't show any sign of a zombie firefox instance. It was more like I installed the new build, ran it. Closed it. Then I changed my Windows Start Menu item then tried to run the build, but no change happened which is why I was checking various command line arguments in my STR.

Ehsan, would bug 568816 fix the privacy command line argument issue here?

Possibly, yes!

The code related to this bug has gone away.