diff --git a/src/Airports/apt_loader.cxx b/src/Airports/apt_loader.cxx
index ff28e89aa..c19c51833 100644
--- a/src/Airports/apt_loader.cxx
+++ b/src/Airports/apt_loader.cxx
@@ -416,7 +416,7 @@ void APTLoader::throwExceptionIfStreamError(const sg_gzifstream& input_stream,
 
     SG_LOG( SG_NAVAID, SG_ALERT,
             "Error while reading '" << path.utf8Str() << "': " << errMsg );
-    throw sg_io_exception("Error reading file (" + errMsg + ")",
+    throw sg_io_exception("APTLoader: error reading file (" + errMsg + ")",
                           sg_location(path));
   }
 }
diff --git a/src/Navaids/fixlist.cxx b/src/Navaids/fixlist.cxx
index 058efed17..fb52d2f6d 100644
--- a/src/Navaids/fixlist.cxx
+++ b/src/Navaids/fixlist.cxx
@@ -166,7 +166,7 @@ void FixesLoader::throwExceptionIfStreamError(
 
     SG_LOG(SG_NAVAID, SG_ALERT,
            "Error while reading '" << path.utf8Str() << "': " << errMsg);
-    throw sg_io_exception("Error reading file (" + errMsg + ")",
+    throw sg_io_exception("FixesLoader: error reading file (" + errMsg + ")",
                           sg_location(path));
   }
 }