diff --git a/plugins/zimbra/zimbra-mailboxsizes b/plugins/zimbra/zimbra-mailboxsizes
index bb075af7..23395c30 100755
--- a/plugins/zimbra/zimbra-mailboxsizes
+++ b/plugins/zimbra/zimbra-mailboxsizes
@@ -59,9 +59,9 @@ if [ "$1" = "config" ]; then
   echo 'graph_scale yes'
   echo 'graph_vlabel Mailboxsize'
   echo 'graph_category Zimbra'
-  /opt/zimbra/bin/zmprov gqu $(hostname)|awk '$3>102400 {sub (/@.*/, "",$1); print $1".label "$1}'
+  /opt/zimbra/bin/zmprov gqu $(hostname)|awk '$3>102400 {sub (/@.*/, "",$1); sub(/\./, "_" ,$1); print $1".label "$1}'
   exit 0
 fi
 
-/opt/zimbra/bin/zmprov gqu $(hostname)|awk '$3>102400 {sub (/@.*/, "",$1); print $1".value "$3}'
+/opt/zimbra/bin/zmprov gqu $(hostname)|awk '$3>102400 {sub (/@.*/, "",  $1); sub(/\./, "_" ,$1); print $1".value "$3}'