X font error
X Error of failed request: BadName (named color or font does not exist)
Major opcode of failed request: 45 (X_OpenFont)
Serial number of failed request: 12
Current serial number in output stream: 13"
If you capture X11 protocol messages using tools like x11trace, you will see it requests font by the following XFLD: '-*-*-medium-r-normal--0-120-*-*-p-0-iso8859-1'.
I don't know why Steam uses old and outdated core X font subsystem, but this can be solved by installing X11 bitmap fonts, like font-adobe-100dpi in Gentoo (initial updating window will be really ugly)."Breakpad exception handler" message
Installing breakpad exception handler for appid(steam)/version(1352224866_client)
This is not an error message; it's the first message Steam normally produces. The problem is that it silently shuts down immediately after.
Most often it happens because of the missing libraries. You can figure them out by running:
LD_LIBRARY_PATH=. ldd * | grep "not found"
Another case can be missing symbols: even if all needed libraries are successfully resolved by their names, some of them can be outdated for Steam and miss needed functions.
You can use LD_DEBUG linker environment variable to detect this:
LD_DEBUG=libs steam 2>&1 | grep error
you can get something like:
<pid>: /home/<user>/Steam/ubuntu12_32/steamui.so: error: symbol lookup error: undefined symbol: _XGetRequest (fatal)
With this information you can try to figure out, which of your system's libraries contain these symbols. For the error above which happens on amd64 Gentoo it's /usr/lib32/libX11.so.6 referenced from steamui.so, updating app-emulation/emul-linux-x86-xlibs to testing version 20121028 solves this issue.Other
Steam launcher can be given DEBUGGER environment variable, i. e. "DEBUGGER=strace steam" will run ~/Steam/ubuntu12_32/steam binary with strace.