diff --git a/eqcorrscan/core/template_gen.py b/eqcorrscan/core/template_gen.py
index 7f361497..dc7007f3 100644
--- a/eqcorrscan/core/template_gen.py
+++ b/eqcorrscan/core/template_gen.py
@@ -521,6 +521,12 @@ def _download_from_client(client, client_type, catalog, data_pad, process_len,
                     "Pick not associated with waveforms, will not use:"
                     " {0}".format(pick))
                 continue
+            if pick.waveform_id.channel_code is None:
+                Logger.error(
+                    f"Missing waveform_id.channel_code for Pick {pick}.")
+                raise TemplateGenError(
+                    "Ensure that all picks have complete "
+                    "waveform_id attributes")
             if all_channels:
                 channel_code = pick.waveform_id.channel_code[0:2] + "?"
             else: