I have the same problem since today :/, but I'm using Ubuntu 12.04 i386
Also tried reinstalling through Ubuntu Software Center, oh forgot to mention, Ubuntu 64 bit 13.04 ATI Radeon 5770 13.4 drivers
Okay it seems that deleting appcache folder worked.
Nothing extracted yet.
After restarting today I couldn't start steam anymore.
Everytime I run steam it shows up the updating steam... window then it dissapears and the login screen doesn't show, Steam process doesn't stop tho.
This is the console output:
aviram@aviram-GA-MA770T-UD3:~$ STEAM_RUNTIME=1 steam
Running Steam on ubuntu 13.04 64-bit
STEAM_RUNTIME is enabled by the user
Installing breakpad exception handler for appid(steam)/version(1378500910_client)
Installing breakpad exception handler for appid(steam)/version(1378500910_client)
unlinked 0 orphaned pipes
removing stale semaphore last operated on by process 4502 with name 0eBlobRegistryMutex_CEE6F505E1572378583004862142347C
removing stale semaphore last operated on by process 4502 with name 0eBlobRegistrySignal_CEE6F505E1572378583004862142347C
removing stale semaphore last operated on by process 4502 with name 0emSteamEngineInstance
removing stale semaphore last operated on by process 4502 with name 0eSteamEngineLock
Gtk-Message: Failed to load module "overlay-scrollbar"
Installing breakpad exception handler for appid(steam)/version(1378500910_client)
[0913/191049:WARNING:proxy_service.cc(958)] PAC support disabled because there is no system implementation
Things I tried:
Delete ClientRegistry.blob
Delete steam.pid
Restart
STEAM_RUNTIME=0
STEAM_DEBUG=1
Nothing works it seems and I have no idea what might have occured that.