diff --git a/api/db/services/document_service.py b/api/db/services/document_service.py
index 12fdc19fef..d5bff3e200 100644
--- a/api/db/services/document_service.py
+++ b/api/db/services/document_service.py
@@ -945,7 +945,7 @@ class DocumentService(CommonService):
                     if t.progress == -1:
                         bad += 1
                     prg += t.progress if t.progress >= 0 else 0
-                    if t.progress_msg.strip():
+                    if (t.progress_msg or "").strip():
                         msg.append(t.progress_msg)
                     priority = max(priority, t.priority)
                 prg /= len(tsks)