post your vmf , there not enough info here
#.VMF file only opens in gmod hammer but crashes in hl2 hammer
lavish obsidian
worthy elk
oh yeah, sorry
somber locust
@worthy elk Just install hammer++ for hl2 and don't bother with this outdated standard software.
https://ficool2.github.io/HammerPlusPlus-Website/download.html
lavish obsidian
i compiled and it works for me , you could do a bit of optimising https://developer.valvesoftware.com/wiki/Optimization/Level_Design apart from that i see no problem