diff --git a/src/bin/proxmox-backup-manager.rs b/src/bin/proxmox-backup-manager.rs
index 6369eb6a..bbc27659 100644
--- a/src/bin/proxmox-backup-manager.rs
+++ b/src/bin/proxmox-backup-manager.rs
@@ -488,7 +488,8 @@ fn datastore_commands() -> CommandLineInterface {
                 CliCommand::new(&api2::config::datastore::API_METHOD_UPDATE_DATASTORE)
                 .arg_param(&["name"])
                 .completion_cb("name", config::datastore::complete_datastore_name)
-        )
+                .completion_cb("gc-schedule", config::datastore::complete_calendar_event)
+    )
         .insert("remove",
                 CliCommand::new(&api2::config::datastore::API_METHOD_DELETE_DATASTORE)
                 .arg_param(&["name"])
diff --git a/src/config/datastore.rs b/src/config/datastore.rs
index 65fe1838..52d7273b 100644
--- a/src/config/datastore.rs
+++ b/src/config/datastore.rs
@@ -123,3 +123,9 @@ pub fn complete_acl_path(_arg: &str, _param: &HashMap<String, String>) -> Vec<St
 
     list
 }
+
+pub fn complete_calendar_event(_arg: &str, _param: &HashMap<String, String>) -> Vec<String> {
+    // just give some hints about possible values
+    ["minutely", "hourly", "daily", "mon..fri", "0:0"]
+        .iter().map(|s| String::from(*s)).collect()
+}