Index: tools/lldb-vscode/lldb-vscode.cpp
===================================================================
--- tools/lldb-vscode/lldb-vscode.cpp
+++ tools/lldb-vscode/lldb-vscode.cpp
@@ -967,10 +967,14 @@
     if (value.GetError().Fail()) {
       response.try_emplace("success", false);
       const char *error_cstr = value.GetError().GetCString();
-      if (error_cstr && error_cstr[0])
-        response.try_emplace("message", std::string(error_cstr));
-      else
+      if (error_cstr && error_cstr[0]) {
+        std::string error_string(error_cstr);
+        if (!llvm::json::isUTF8(error_string))
+          error_string = llvm::json::fixUTF8(std::move(error_string));
+        response.try_emplace("message", error_string);
+      } else {
         response.try_emplace("message", "evaluate failed");
+      }
     } else {
       SetValueForKey(value, body, "result");
       auto value_typename = value.GetType().GetDisplayTypeName();