diff --git a/pressure-vessel/wrap.c b/pressure-vessel/wrap.c
index 5c15be3736ce0602f4d0ce3ea61216622d50a867..80865c7c9d0c6a6ff9bda5b6bd912a92785fac11 100644
--- a/pressure-vessel/wrap.c
+++ b/pressure-vessel/wrap.c
@@ -303,6 +303,7 @@ static const EnvMount known_required_env[] =
     { "PRESSURE_VESSEL_FILESYSTEMS_RO",
       ENV_MOUNT_FLAGS_READ_ONLY | ENV_MOUNT_FLAGS_COLON_DELIMITED },
     { "PRESSURE_VESSEL_FILESYSTEMS_RW", ENV_MOUNT_FLAGS_COLON_DELIMITED },
+    { "PROTON_LOG_DIR", ENV_MOUNT_FLAGS_NONE },
     { "STEAM_COMPAT_APP_LIBRARY_PATH", ENV_MOUNT_FLAGS_DEPRECATED },
     { "STEAM_COMPAT_APP_LIBRARY_PATHS",
       ENV_MOUNT_FLAGS_COLON_DELIMITED | ENV_MOUNT_FLAGS_DEPRECATED },