diff --git a/src/client/main.cpp b/src/client/main.cpp
index 97ee8417..324eec3c 100644
--- a/src/client/main.cpp
+++ b/src/client/main.cpp
@@ -103,7 +103,7 @@ FARPROC load_binary(const launcher::mode mode, uint64_t* base_address)
 				}
 				else
 				{
-					MSG_BOX_WARN("Could not find Steam in the registry. If Steam is not installed, you must install it for H1-Mod to work.");
+					throw std::runtime_error("Could not find Steam in the registry. If Steam is not installed, you must install it for H1-Mod to work.");
 				}
 
 				check_for_steam_install = true;