diff --git a/checkin_notes b/checkin_notes
index c612a212ac..c2d501fd30 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -648,3 +648,14 @@ David  22 Jan 2010
         result.inc
     sched/
         transitioner.cpp
+
+David  25 Jan 2010
+    - transitioner: fix bug where WUs with error_mask <> 0 keep
+        transitioning every 10 days, hence never become eligible for purging.
+        The problem: the transitioner has a "safety net" where,
+        if the WU doesn't have a canonical result,
+        it arranges for another transition in 10 days.
+        Skip this if error_mask<>0.
+
+    sched/
+        transitioner.cpp
diff --git a/sched/transitioner.cpp b/sched/transitioner.cpp
index d652b0f5bb..526a63238b 100644
--- a/sched/transitioner.cpp
+++ b/sched/transitioner.cpp
@@ -540,12 +540,12 @@ int handle_wu(
 
     // compute next transition time = minimum timeout of in-progress results
     //
-    if (wu_item.canonical_resultid) {
+    if (wu_item.canonical_resultid || wu_item.error_mask) {
         wu_item.transition_time = INT_MAX;
     } else {
-        // If there is no canonical result,
-        // make sure that the transitioner will 'see' this WU again.
-        // In principle this is NOT needed, but it is one way to make
+        // If there is no canonical result and no WU-level error,
+        // make sure that the transitioner will process this WU again.
+        // In principle this is not needed, but it makes
         // the BOINC back-end more robust.
         //
         const int ten_days = 10*86400;