diff --git a/src/simulation/GOLString.cpp b/src/simulation/GOLString.cpp
index 405255de3..859bd0ed4 100644
--- a/src/simulation/GOLString.cpp
+++ b/src/simulation/GOLString.cpp
@@ -13,6 +13,10 @@ int ParseGOLString(const String &value)
 	{
 		begin |= 1U << (it[0] - '0');
 	}
+	if (!begin)
+	{
+		return -1;
+	}
 
 	// Must have a /S immediately afterwards
 	if (it < value.end() - 1 && it[0] == '/' && it[1] == 'S')