diff --git a/clusterio_0.0.3/control.lua b/clusterio_0.0.3/control.lua
index ca717c0a..d7fa6675 100644
--- a/clusterio_0.0.3/control.lua
+++ b/clusterio_0.0.3/control.lua
@@ -444,6 +444,7 @@ function UpdateInvCombinators()
 
   local items = game.item_prototypes
   local fluids = game.fluid_prototypes
+  local virtuals = game.virtual_signal_prototypes
   if global.invdata then
     for name,count in pairs(global.invdata) do
       if virtuals[name] then