diff --git a/pySPM/Bruker.py b/pySPM/Bruker.py
index c7c696f..dfbd7d1 100644
--- a/pySPM/Bruker.py
+++ b/pySPM/Bruker.py
@@ -158,6 +158,8 @@ def get_channel(
                     )
                 except KeyError:
                     continue
+                except UnboundLocalError:
+                    continue
             else:
                 _type = "Bruker AFM"
                 try:
@@ -166,6 +168,8 @@ def get_channel(
                     )
                 except KeyError:
                     continue
+                except UnboundLocalError:
+                    continue
             result = re.match(r'([^ ]+) \[([^]]*)] "([^"]*)"', layer_name).groups()
             if result[2] == channel:
                 if debug: