Doesn't remember my video settings

Just built a new PC.
Each time I start Black Mesa, it comes up in 1024 x 768 (3:4 ratio), and no AA.
Each time I have to switch to 16:10, 1920 x 1200, 4xAA (etc).
My system is easily powerful enough to handle these settings.
But when I quit, it doesn’t remember anything, and I have to do it all again next time I start.

NB: Doesn’t happen for other Steam/Source games (tested Half Life 2 & Portal 2)

MoBo : ASUS P8 Z77-V LX
CPU : i5 3570 @3.4GHz
SDD : Intel 520 Series 240GB (Steam on this)
HDD : Western Digital Caviar Green 2TB 64MB Cache
GPU : ASUS GeForce GTX 670 DirectCU II
OS : Windows 7 Home Premium 64-bit
PSU : Seasonic X-650
Audio : Roland Quad Capture

Steam freshly installed & activated,
SteamApps folder copied across

check your BMS shortcut and autoexec.cfg for commands like “dxlevel” and take them off

alternatively, you could put -width 1920 -height 1200 in the shortcut…

Thanks - that was it. I was experimenting with dxlevel settings on my previous (horribly underpowered) computer, and they got copied across (via the SteamApps folder)

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.