My ancient SuSe box, which works fine, started having problems several months ago with firefox freezing, ps would always show its wchan as futex_ . I would kill & restart firefox, which would run for 2 seconds to 4 days, no apparent pattern to failure. It just now updated, after i killed a stuck instance. Now it refuses to start AT ALL. Never shows up in ps. When started by CLI, it gives the err listed in subject: symbol lookup error: /usr/lib64/firefox21/libxul.so: undefined symbol: FcConfigReference firefox21 is soft symlinked to firefox, don't know why, but the files in that dir, including libxul.so, have todays' date. Do i need a different .so? The system info shown is for my old win xp box, which is currently the only thing firefox will run on, as the ubuntu 12.04 firefox also stopped working today. The system having the problem is running SLES 11.