diff --git a/src/driver_dynamic.cc b/src/driver_dynamic.cc
index a95f74f..618efaa 100644
--- a/src/driver_dynamic.cc
+++ b/src/driver_dynamic.cc
@@ -237,7 +237,14 @@ XMQProceed DriverDynamic::add_detect(XMQDoc *doc, XMQNode *detect, DriverInfo *d
 XMQProceed DriverDynamic::add_use(XMQDoc *doc, XMQNode *field, DriverDynamic *dd)
 {
     string name = xmqGetString(doc, field, ".");
-    dd->addOptionalLibraryFields(name);
+    bool ok = dd->addOptionalLibraryFields(name);
+    if (!ok)
+    {
+        warning("(driver) error in %s, unknown library field: %s \n",
+                dd->fileName().c_str(),
+                name.c_str());
+    }
+
     return XMQ_CONTINUE;
 }
 
diff --git a/src/meters.cc b/src/meters.cc
index 2bb5a3c..3ec4e6b 100644
--- a/src/meters.cc
+++ b/src/meters.cc
@@ -2679,7 +2679,7 @@ bool checkIf(set<string> &fields, const char *s)
     return false;
 }
 
-void checkFieldsEmpty(set<string> &fields, string name)
+bool checkFieldsEmpty(set<string> &fields, string driver_name)
 {
     if (fields.size() > 0)
     {
@@ -2687,12 +2687,14 @@ void checkFieldsEmpty(set<string> &fields, string name)
         for (auto &s : fields) { info += s+" "; }
 
         warning("(meter) when adding common fields to driver %s, these fields were not found: %s\n",
-                name.c_str(),
+                driver_name.c_str(),
                 info.c_str());
+        return false;
     }
+    return true;
 }
 
-void MeterCommonImplementation::addOptionalLibraryFields(string field_names)
+bool MeterCommonImplementation::addOptionalLibraryFields(string field_names)
 {
     set<string> fields = splitStringIntoSet(field_names, ',');
 
@@ -3095,6 +3097,12 @@ void MeterCommonImplementation::addOptionalLibraryFields(string field_names)
             .set(VIFRange::HeatCostAllocation)
             );
     }
+
+    if (!checkFieldsEmpty(fields, name()))
+    {
+        return false;
+    }
+    return true;
 }
 
 const char *toString(VifScaling s)
diff --git a/src/meters_common_implementation.h b/src/meters_common_implementation.h
index 79ea2a5..c1c87cd 100644
--- a/src/meters_common_implementation.h
+++ b/src/meters_common_implementation.h
@@ -204,7 +204,7 @@ protected:
 
     std::string decodeTPLStatusByte(uchar sts);
 
-    void addOptionalLibraryFields(string fields);
+    bool addOptionalLibraryFields(string fields);
 
     vector<string> &selectedFields() { return selected_fields_; }
     void setSelectedFields(vector<string> &f) { selected_fields_ = f; }
diff --git a/src/wmbus_rtlwmbus.cc b/src/wmbus_rtlwmbus.cc
index a6ce02a..13e8d51 100644
--- a/src/wmbus_rtlwmbus.cc
+++ b/src/wmbus_rtlwmbus.cc
@@ -168,7 +168,7 @@ shared_ptr<BusDevice> openRTLWMBUS(Detected detected,
             args.push_back("-h");
             invokeShellCaptureOutput(rtl_wmbus, { "-h" }, {}, &out, true);
             debug("(rtlwmbus) help %s\n", out.c_str());
-            if (out.find("-f exit if flow") != string::npos)
+            if (out.find("-f exit") != string::npos)
             {
                 add_f = " -f";
             }