diff --git a/imap_filter/imap_filter.py b/imap_filter/imap_filter.py
index 5fe20e3..6920d17 100644
--- a/imap_filter/imap_filter.py
+++ b/imap_filter/imap_filter.py
@@ -301,10 +301,18 @@ class ImapFilter:
         message = email.message_from_string(part)
         decoded_field = email.header.decode_header(message.get(mfilter['field'], ""))
         for raw_field_data in decoded_field:
-            if isinstance(raw_field_data[0], str):
+            if isinstance(raw_field_data[0], str):  
                 field_data = raw_field_data[0]
             else:
-                field_data = raw_field_data[0].decode()
+                try:
+                    field_data = raw_field_data[0].decode()
+                except UnicodeDecodeError as error:
+                    self._log.error(
+                        "Error decoding field data as UTF-8. Data: %s. Error: %s",
+                        raw_field_data[0],
+                        error
+                    )
+                    break
             if 'regexp' in mfilter:
                 if not isinstance(mfilter['regexp'], list):
                     mfilter['regexp'] = [ mfilter['regexp'] ]