diff --git a/site_ansto/instrument/reflectometer/config/scan/scan.tcl b/site_ansto/instrument/reflectometer/config/scan/scan.tcl
index 23fad843..2d556950 100644
--- a/site_ansto/instrument/reflectometer/config/scan/scan.tcl
+++ b/site_ansto/instrument/reflectometer/config/scan/scan.tcl
@@ -2,11 +2,12 @@ source $cfPath(scan)/scan_common_1.tcl
 ::scan::runscan_reset_position true
 ##
 # @brief Make sure that the chopper is ready before starting a scan.
-proc ::scan::pre_hmm_scan_prepare {} {
-  if [catch {::histogram_memory::tochfreq} errmsg] {
-    return -code error $errmsg
-  } 
-}
+# SICS-635 Don't set histmem freq because it takes too long.
+#proc ::scan::pre_hmm_scan_prepare {} {
+#  if [catch {::histogram_memory::tochfreq} errmsg] {
+#    return -code error $errmsg
+#  } 
+#}
 
 proc ::scan::isc_initialize {} {
   ::scan::ic_initialize