diff --git a/src/main/resources/assets/opencomputers/loot/OpenOS/init.lua b/src/main/resources/assets/opencomputers/loot/OpenOS/init.lua
index da7148a11..34cd4c5e3 100644
--- a/src/main/resources/assets/opencomputers/loot/OpenOS/init.lua
+++ b/src/main/resources/assets/opencomputers/loot/OpenOS/init.lua
@@ -184,7 +184,7 @@ while true do
   motd()
   local result, reason = os.execute(os.getenv("SHELL"))
   if not result then
-    io.stderr:write((tostring(reason) or "unknown error") .. "\n")
+    io.stderr:write((reason ~= nil and tostring(reason) or "unknown error") .. "\n")
     io.write("Press any key to continue.\n")
     os.sleep(0.5)
     require("event").pull("key")