Why this happens?
Long story short, 'steam' makes connections to the steam's linked networks to then attempt connection to steam networks before game services to make sure your not connecting to unofficial cracked servers, as I've been told. If it fails, then your game or 'hl2.exe' crashes.
Either do one of the following or it may just be the client build as I had these issues with last build.
- Verify the game's cache via steam.
- Restart the steam client as the process: 'SteamService.exe' may have created an invalid handle.
1.) Sometimes, a dll might have an invalid signature, it happens out of the blue.
Fix: Verify the game's internal files.
2.) 'SteamService.exe' may have created an invalid handle.
Fix: Force-Close using CTRL + ALT + DEL and open task manager. Then, go to the processes tab and look for 'steam.exe' left click once and cllick the end the task button Then restart steam.
3). If you still have issues, contact via cooments and I'll get to the bottom of your issue. Hope, I helped.