(In reply to Ulrich Windl from comment #0) > To make things worse, "Yast2 sw_single" crashes when trying to revert to the > previous version of Firefox. That's solved: If you select the "remove Firefox 34.0.5", YaST crashes; if you select "downgrade ..." it works. So I went back to the previous version (MozillaFirefox-33.0-1.90.1.i586), and everything works again!