I had the same problem. I disabled all extensions and then enabled them one by one and tested it (make sure not to test in safe mode). For me it was firegesture that kept firefox from starting.

I had the same problem and "0" extensions on OpenSUSE 10.2... btw: with -profilemanager or -P firefox infinitely crash..

strace log: execve("/usr/lib/firefox/firefox", ["/usr/lib/firefox/firefox"], 94 vars */) = 0 brk(0) = 0x805e000 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb77a7000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/tls/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/tls/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/tls/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/tls/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/tls/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/tls/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/tls/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/tls", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/xulrunner-1.9.2.4/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/xulrunner-1.9.2.4", ) = 0 open("/alt/usr/lib/tls/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/tls/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/tls/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/tls/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/tls/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/tls/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/tls/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/tls", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/alt/usr/lib", ) = 0 open("/usr/lib/tls/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib", ) = 0 open("/usr/lib/firefox/tls/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/tls/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/tls/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/tls/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/tls/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/tls/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/tls/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/tls", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/i686/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/i686/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/i686/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/i686", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/sse2/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox/sse2", 0xbf95db28) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/firefox", ) = 0 open("/etc/ld.so.cache", O_RDONLY) = 3 fstat64(3, ) = 0 mmap2(NULL, 200606, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7776000 close(3) = 0 open("/lib/libpthread.so.0", O_RDONLY) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320H\0\0004\0\0\0\314#\t\0\0\0\0\0004\0 \0\t\0(\0/\0,\0\6\0\0\0004\0\0\0004\0\0\0004\0\0\0 \1\0\0 \1\0\0\5\0\0\0\4\0\0\0\3\0\0\0\f\17\1\0\f\17"..., 512) = 512 fstat64(3, ) = 0 mmap2(NULL, 102892, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb775c000 fadvise64(3, 0, 102892, POSIX_FADV_WILLNEED) = 0 mmap2(0xb7772000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15) = 0xb7772000 mmap2(0xb7774000, 4588, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7774000 close(3) = 0 open("/usr/lib/xulrunner-1.9.2.4/libasound.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/libasound.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/lib/libasound.so.2", O_RDONLY) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0P\227\1\0004\0\0\0\\J(\0\0\0\0\0004\0 \0\5\0(\0&\0#\0\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\300\f\0\4\300\f\0\5\0\0\0\0\20\0\0\1\0\0\0\4\300\f\0\4"..., 512) = 512 fstat64(3, ) = 0 mmap2(NULL, 852136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb768b000 fadvise64(3, 0, 852136, POSIX_FADV_WILLNEED) = 0 mmap2(0xb7758000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xcc) = 0xb7758000 close(3) = 0 open("/usr/lib/xulrunner-1.9.2.4/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/alt/usr/lib/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/lib/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/lib/firefox/libdl.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/libdl.so.2", O_RDONLY) = 3

[...]

poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 772484}, NULL) = 0 futex(0xb3e4d408, 0x85 /* FUTEX_??? */, 1) = 1 access("/home/zator/.mozilla/firefox/7pilqh84.default/prefs.js", F_OK) = 0 lstat64("/home", ) = 0 lstat64("/home/zator", ) = 0 lstat64("/home/zator/.mozilla", ) = 0 lstat64("/home/zator/.mozilla/firefox", ) = 0 lstat64("/home/zator/.mozilla/firefox/7pilqh84.default", ) = 0 lstat64("/home/zator/.mozilla/firefox/7pilqh84.default/prefs.js", ) = 0 stat64("/home/zator/.mozilla/firefox/7pilqh84.default/prefs.js", ) = 0 open("/home/zator/.mozilla/firefox/7pilqh84.default/prefs.js", O_WRONLY|O_CREAT|O_TRUNC|O_EXCL|O_LARGEFILE, 0600) = -1 EEXIST (File exists) open("/home/zator/.mozilla/firefox/7pilqh84.default/prefs-1.js", O_WRONLY|O_CREAT|O_TRUNC|O_EXCL|O_LARGEFILE, 0600) = 27 close(27) = 0 open("/home/zator/.mozilla/firefox/7pilqh84.default/prefs-1.js", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0600) = 27 write(27, "# Mozilla User Preferences\n\n/* Do not edit this file.\n *\n * If you make changes to this file while "..., 1004) = 1004 fsync(27) = 0 close(27) = 0 rename("/home/zator/.mozilla/firefox/7pilqh84.default/prefs-1.js", "/home/zator/.mozilla/firefox/7pilqh84.default/prefs.js") = 0 gettimeofday({1278093840, 938976}, NULL) = 0 gettimeofday({1278093840, 939024}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 939234}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 939437}, NULL) = 0 gettimeofday({1278093840, 939483}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 939683}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 939910}, NULL) = 0 gettimeofday({1278093840, 939955}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 940152}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 940350}, NULL) = 0 gettimeofday({1278093840, 940395}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 940592}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 940791}, NULL) = 0 gettimeofday({1278093840, 940837}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 941033}, NULL) = 0 ioctl(3, FIONREAD, [0]) = 0 poll([ , , , , , , , , ], 9, 0) = 0 gettimeofday({1278093840, 941243}, NULL) = 0 close(20) = 0 close(21) = 0 munmap(0xb23d4000, 155254) = 0 close(26) = 0 write(19, "\0", 1) = 1 futex(0xb4792bd8, FUTEX_WAIT, 10250, NULL) = 0 close(23) = 0 close(24) = 0 unlink("/home/zator/.mozilla/firefox/7pilqh84.default/lock") = 0 writev(13, [{"GIOP\1\2\1\5\0\0\0\0", 12}], 1) = 12 close(13) = 0 writev(11, [{"GIOP\1\2\1\5\0\0\0\0", 12}], 1) = 12 close(11) = 0 close(9) = 0 close(8) = 0 unlink("/tmp/orbit-zator/linc-2809-0-1699dc727718e") = 0 close(12) = 0 exit_group(1) = ?

Thank you dworz. The culprit turned out to be the "gmail notifier" add-on. Without it, firefox starts as it should.

Cheers!