diff --git a/broker/JFJochServices.cpp b/broker/JFJochServices.cpp
index 1d30ed54..b5913a81 100644
--- a/broker/JFJochServices.cpp
+++ b/broker/JFJochServices.cpp
@@ -122,6 +122,14 @@ JFJochServicesOutput JFJochServices::Stop() {
                                     ret.receiver_output.received_packets[i], ret.receiver_output.expected_packets[i]);
                 }
             }
+
+            // A writer that broke mid-run (e.g. a lost connection) leaves a truncated file.
+            // Surface that as a failed acquisition instead of silently reporting success.
+            if (!ret.receiver_output.writer_err.empty())
+                throw JFJochException(JFJochExceptionCategory::FileWriteError,
+                                      "Writer error, written data may be incomplete: "
+                                      + ret.receiver_output.writer_err);
+
             logger.Info("    ... finished with success");
         } catch (const JFJochException &e) {
             logger.Error("   ... finished with error {}", e.what());