diff --git a/hooks/backup/27-data_xmpp b/hooks/backup/27-data_xmpp
index 2cd93e02b..078184ed8 100644
--- a/hooks/backup/27-data_xmpp
+++ b/hooks/backup/27-data_xmpp
@@ -9,5 +9,5 @@ source /usr/share/yunohost/helpers
 # Backup destination
 backup_dir="${1}/data/xmpp"
 
-ynh_backup /var/lib/metronome "${backup_dir}/var_lib_metronome"
-ynh_backup /var/xmpp-upload/ "${backup_dir}/var_xmpp-upload"
+ynh_backup /var/lib/metronome "${backup_dir}/var_lib_metronome" --not_mandatory
+ynh_backup /var/xmpp-upload/ "${backup_dir}/var_xmpp-upload" --not_mandatory
diff --git a/hooks/restore/27-data_xmpp b/hooks/restore/27-data_xmpp
index 02a4c6703..f07ac6a33 100644
--- a/hooks/restore/27-data_xmpp
+++ b/hooks/restore/27-data_xmpp
@@ -1,4 +1,11 @@
 backup_dir="$1/data/xmpp"
 
-cp -a $backup_dir/var_lib_metronome/. /var/lib/metronome
-cp -a $backup_dir/var_xmpp-upload/. /var/xmpp-upload
+if [[ -e $backup_dir/var_lib_metronome/ ]]
+then
+    cp -a $backup_dir/var_lib_metronome/. /var/lib/metronome
+fi
+
+if [[ -e $backup_dir/var_xmpp-upload ]]
+then
+    cp -a $backup_dir/var_xmpp-upload/. /var/xmpp-upload
+fi