diff --git a/ChangeLog b/ChangeLog
index d228c982..53d6147d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -16614,3 +16614,6 @@
 	* Added support for DMA bus-mastering to the HPI driver.
 2018-03-18 Fred Gleason <fredg@paravelsystems.com>
 	* Updated switch() statement formatting in 'rdhpi/'.
+2018-03-18 Fred Gleason <fredg@paravelsystems.com>
+	* Fixed a bug in rdlogmanager(1) that caused DB corruption when
+	a clock was deleted while still being assigned to a grid.
diff --git a/rdlogmanager/list_clocks.cpp b/rdlogmanager/list_clocks.cpp
index eacdf88f..1e568de6 100644
--- a/rdlogmanager/list_clocks.cpp
+++ b/rdlogmanager/list_clocks.cpp
@@ -609,9 +609,10 @@ void ListClocks::DeleteClock(QString clockname)
   base_name.replace(" ","_");
 
   //
-  // Delete Active Clocks
+  // Clear Active Clocks
   //
-  sql=QString("delete from SERVICE_CLOCKS where ")+
+  sql=QString("update SERVICE_CLOCKS set ")+
+    "CLOCK_NAME=null where "+
     "CLOCK_NAME=\""+RDEscapeString(clockname)+"\"";
   q=new RDSqlQuery(sql);
   delete q;