diff --git a/code/modules/admin/view_variables/modify_variables.dm b/code/modules/admin/view_variables/modify_variables.dm
index fd88f7f88ab..491ff490f7d 100644
--- a/code/modules/admin/view_variables/modify_variables.dm
+++ b/code/modules/admin/view_variables/modify_variables.dm
@@ -193,9 +193,10 @@ GLOBAL_PROTECT(VVpixelmovement)
 		else
 			variable = L[index]
 			//EXPERIMENTAL - Keep old associated value while modifying key, if any
-			var/found = L[variable]
-			if(!isnull(found))
-				old_assoc_value = found
+			if(IS_VALID_ASSOC_KEY(variable))
+				var/found = L[variable]
+				if(!isnull(found))
+					old_assoc_value = found
 			//
 
 	default = vv_get_class(objectvar, variable)