diff --git a/r3bsource/base/R3BUcesbSource.cxx b/r3bsource/base/R3BUcesbSource.cxx
index f17fe0b98..a2a82e5a5 100644
--- a/r3bsource/base/R3BUcesbSource.cxx
+++ b/r3bsource/base/R3BUcesbSource.cxx
@@ -172,13 +172,12 @@ Bool_t R3BUcesbSource::InitUnpackers()
     {
         R3BLOG(warn, "ext_data_clnt::setup() failed to map all items:");
         ext_data_struct_info_print_map_success(fStructInfo, stderr, map_ok);
-        /* FairRunOnline::Init() ignores the return value from
-         * GetSource()->InitUnpackers(); so do a (FATAL) error.
-         */
-        R3BLOG(error,
-               "ext_data_clnt::setup() mapping failure may "
-               "cause unexpected analysis results due to missing "
-               "data members. Unpacker needs fixing.");
+	/* FairRunOnline::Init() ignores the return value from
+	 * GetSource()->InitUnpackers(); so do a FATAL error.
+	 */
+        R3BLOG(fatal, "ext_data_clnt::setup() mapping failure may "
+	       "cause unexpected analysis results due to missing "
+	       "data members.  Unpacker needs fixing.");
         return kFALSE;
     }