I recently had a debian install where Steam would not launch. Here is how I fixed it when it.

Note: This is for nVidia based GPU systems

Error Screen

You are missing the following 32-bit libraries, and Steam may not run: libGL.so.1

Packages Required

These packages are missing and will fix the above error.

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt install libgl1-mesa-dri:i386 libgl1:i386
sudo apt-get upgrade steam -f
sudo apt install nvidia-driver-libs:i386

Launch Steam

You now can launch steam and have it launch properly.