diff --git a/pollen/private/ts.rktd b/pollen/private/ts.rktd
index 43a32f2..977c87c 100644
--- a/pollen/private/ts.rktd
+++ b/pollen/private/ts.rktd
@@ -1 +1 @@
-1560436450
+1560481034
diff --git a/pollen/render.rkt b/pollen/render.rkt
index 7540d71..808a567 100644
--- a/pollen/render.rkt
+++ b/pollen/render.rkt
@@ -55,7 +55,8 @@
   ;; Using reset-modification-dates is sort of like session control.
   (reset-mod-date-hash!)
   (cond
-    [parallel?
+    ;; disable parallel processing until concurrency problems are sorted
+    #;[parallel?
      (define worker-places
        (for/list ([i (in-range (processor-count))])
          (place ch