I figured I better post a SOLVED for this. In the main thread it is still open as to whether a new bug should be posted. Short form: don't have FF check and set itself as default browser, rather run gnome-default-applications-properties and select the firefox icon rather than "Custom" command. On Tue, 2008-12-23 at 10:58 -0500, William L. Maltby wrote: > On Mon, 2008-12-22 at 18:49 -0500, William L. Maltby wrote: > > SYNOPSIS: Bug between Firefox and > > > > gnome-default-applications-properties > > > > somewhere. > > > > When FF is set to check to see if it is the default browser and it is > > not and the user selects "Yes" to make it the default, FF writes the > > full path to the /usr/lib instance in the command and sets the preferred > > browser to "Custom". > > > > This causes the symptoms that have been seen, including the truncation > > of pluginreg.dat. > > > > If the user responds "No" when FF asks if it should be the default > > browser, the settings that were selected in > > > > gnome-default-applications-properties > > > > hold and the adverse symptoms are not seen. > > > > WORKAROUND: tell firefox "No" or to _not_ check to see if it is the > > default browser after running gnome-default-applications-properties and > > selecting it there. > > > > CONCLUSION: The gnome-default-applications-properties apparently gets > > the binary in /usr/bin while FF itself bypasses this binary and goes > > directly to the /usr/lib/ firefox instance. In this case the adverse > > symptoms are seen. > > > > Bug somewhere, I presume FF since the > > > > gnome-default-applications-properties > > > > settings work OK and it accesses the binary in /usr/bin. > > > > More detail that you ever wanted to know follows. > > <snip> > > BTW, I forgot to pull a basic check, so here it is. > > $ rpm -qf /usr/lib/firefox-3.0.5/firefox /usr/bin/firefox > firefox-3.0.5-1.el5.centos.i386 > firefox-3.0.5-1.el5.centos.i386 >