diff --git a/src/libslic3r/PlaceholderParser.cpp b/src/libslic3r/PlaceholderParser.cpp
index 1d12c0b05..8ca131f34 100644
--- a/src/libslic3r/PlaceholderParser.cpp
+++ b/src/libslic3r/PlaceholderParser.cpp
@@ -798,6 +798,8 @@ namespace client
                     opt_key_str.resize(opt_key_str.size() - 1);
                 opt = ctx->resolve_symbol(opt_key_str);
             }
+            if (opt == nullptr)
+                ctx->throw_exception("Variable does not exist", opt_key);
             if (! opt->is_vector())
                 ctx->throw_exception("Trying to index a scalar variable", opt_key);
             const ConfigOptionVectorBase *vec = static_cast<const ConfigOptionVectorBase*>(opt);