trying to log in both as root/user , KDE splash screen loads 3 first icons (disk , settings and globe) freezes and if i click anywhere on the screen crash report pops up
with this data :

Application: KDE Daemon (kded4), signal: Segmentation fault
Using host libthread_db library "/lib/libthread_db.so.1".
[KCrash Handler]
#6 0x4c11d50c in _dl_relocate_object () from /lib/ld-linux.so.2
#7 0x4c1248b2 in dl_open_worker () from /lib/ld-linux.so.2
#8 0x4c12048e in _dl_catch_error () from /lib/ld-linux.so.2
#9 0x4c1240b4 in _dl_open () from /lib/ld-linux.so.2
#10 0x4c304cbe in dlopen_doit () from /lib/libdl.so.2
#11 0x4c12048e in _dl_catch_error () from /lib/ld-linux.so.2
#12 0x4c305472 in _dlerror_run () from /lib/libdl.so.2
#13 0x09b18e28 in ?? ()

This looks like a failure to load a KDE Daemon module - does ~/.xsession-errors contain information concerning which module it was trying to load? I expect it should have something along the lines of "symbol lookup failure:" or similar.

same happens to me , my KDE4 stops working after an upgrade using yum
if some one has a solution please tell me wath do i have to do... im using xfce right now

Application: KDE Daemon (kded4), signal: Segmentation fault
Using host libthread_db library "/lib/libthread_db.so.1".
[KCrash Handler]
#6 0x4d41d50c in _dl_relocate_object () from /lib/ld-linux.so.2
#7 0x4d4248b2 in dl_open_worker () from /lib/ld-linux.so.2
#8 0x4d42048e in _dl_catch_error () from /lib/ld-linux.so.2
#9 0x4d4240b4 in _dl_open () from /lib/ld-linux.so.2
#10 0x4d631cbe in dlopen_doit () from /lib/libdl.so.2
#11 0x4d42048e in _dl_catch_error () from /lib/ld-linux.so.2
#12 0x4d632472 in _dlerror_run () from /lib/libdl.so.2
#13 0x0874ab18 in ?? ()

Does attempting to open System Settings (after login completes, use Alt + F2 after closing the crash dialog) and browsing to the Notification settings cause System Settings to crash as well.

I suspect this is a variant of the nvidia-libGL/glibc dlopen bug, see also:
https://bugzilla.redhat.com/show_bug.cgi?id=751891
https://bugs.kde.org/show_bug.cgi?id=286388

workarounds include:
* don't use nvidia driver (libGL)
* re-run glibc's prelink whenever you update kdelibs
* disable glibc prelink

Hi same ocur to my instalation of FC17

i use nouveau video driver

Application: KDE Daemon (kded4), signal: Segmentation fault
Using host libthread_db library "/lib/libthread_db.so.1".
[KCrash Handler]
#6 0x4d41d50c in _dl_relocate_object () from /lib/ld-linux.so.2
#7 0x4d4248b2 in dl_open_worker () from /lib/ld-linux.so.2
#8 0x4d42048e in _dl_catch_error () from /lib/ld-linux.so.2
#9 0x4d4240b4 in _dl_open () from /lib/ld-linux.so.2
#10 0x4d631cbe in dlopen_doit () from /lib/libdl.so.2
#11 0x4d42048e in _dl_catch_error () from /lib/ld-linux.so.2
#12 0x4d632472 in _dlerror_run () from /lib/libdl.so.2
#13 0x0874ab18 in ?? ()

@vpass: Does your system use the proprietary Nvidia driver?