This is probably a duplicate of other issues here, such as #3273.
Long story short, use the Arch workaround.
Arch workaround worked for me, thanks
After the first command Steam started updating and disappeared without saying anything
I had to run the second command too to get it to start
The Steam package in Ubuntu 15.10's software center does not work. Did you try downloading directly from Steam? That solved my issue.
Closing as fixed in steam's 1.0.0.55 bootstrap runtime.
Nothing extracted yet.
I get this error
steam
Running Steam on ubuntu 15.10 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(0)
libGL error: unable to load driver: r600_dri.so
libGL error: driver pointer missing
libGL error: failed to load driver: r600
libGL error: unable to load driver: swrast_dri.so
libGL error: failed to load driver: swrast