diff --git a/crates/features/src/lock/mod.rs b/crates/features/src/lock/mod.rs
index b19e4ff..d44a26d 100644
--- a/crates/features/src/lock/mod.rs
+++ b/crates/features/src/lock/mod.rs
@@ -27,6 +27,32 @@ use store::{
     write::{AnyClass, BatchBuilder, ValueClass},
 };
 use trc::AddContext;
+
+/// Rung when a lock is written, so this node's expiry timer re-reads the
+/// `until` dates (AL-5): a delegation ends at its time, not at a sweep.
+pub static UNTIL_CHANGED: tokio::sync::Notify = tokio::sync::Notify::const_new();
+
+/// The soonest `until` still ahead of `now`, across every lock.
+pub fn next_until(locks: &[Lock], now: u64) -> Option<u64> {
+    locks
+        .iter()
+        .flat_map(|lock| &lock.delegates)
+        .filter_map(|delegate| delegate.until)
+        .filter(|until| *until > now)
+        .min()
+}
+
+/// Locks with a delegation that ended in `(after, now]`.
+pub fn ended_between(locks: &[Lock], after: u64, now: u64) -> impl Iterator<Item = u32> + '_ {
+    locks
+        .iter()
+        .filter(move |lock| {
+            lock.delegates
+                .iter()
+                .any(|d| d.until.is_some_and(|until| until > after && until <= now))
+        })
+        .map(|lock| lock.account_id)
+}
 use types::{
     acl::{Acl, AclGrant},
     collection::Collection,
@@ -240,10 +266,19 @@ pub fn merge_grants(
             if is_current(new, delegate.account_id) {
                 continue;
             }
-            let before = noted(old, delegate.account_id)
+            let note = noted(old, delegate.account_id);
+            let before = note
+                .as_ref()
                 .map(|r| Bitmap::from(r.rights))
                 .unwrap_or_default();
             set(&mut acls, delegate.account_id, before);
+            // Still listed but past its `until`: keep the note, so running
+            // this again puts back the same share instead of removing it
+            if let Some(note) = note
+                && new.is_some_and(|new| new.delegate(delegate.account_id).is_some())
+            {
+                replaced.push(note);
+            }
         }
     }
 
@@ -415,8 +450,9 @@ pub async fn set(data: &Store, lock: &Lock, previous: Option<&Lock>) -> trc::Res
     batch.set(class(KIND_LOCK, &[lock.account_id]), Json(lock).serialize()?);
     data.write(batch.build_all())
         .await
-        .caused_by(trc::location!())
-        .map(|_| ())
+        .caused_by(trc::location!())?;
+    UNTIL_CHANGED.notify_one();
+    Ok(())
 }
 
 /// Removes a lock and its delegate index.
@@ -532,6 +568,57 @@ mod tests {
         assert!(after.contains(&AclGrant { account_id: 3, grants: read }));
     }
 
+    #[test]
+    fn an_expired_delegation_gives_back_its_share_every_time() {
+        let earlier: Bitmap<Acl> = Bitmap::from_iter([Acl::Read]);
+        let note = Replaced {
+            collection: Collection::Mailbox as u8,
+            document_id: 5,
+            delegate: 2,
+            rights: u64::from(earlier),
+        };
+        let mut ending = delegate(2, Access::Full);
+        ending.until = Some(200);
+        let lock = lock_with(vec![ending], vec![note.clone()]);
+        let during = vec![AclGrant {
+            account_id: 2,
+            grants: Access::Full.grants(Collection::Mailbox, false),
+        }];
+
+        // At its `until`, the share it had before comes back, and the note stays
+        let mut replaced = Vec::new();
+        let after = merge_grants(&during, Collection::Mailbox, 5, false, Some(&lock), Some(&lock), 300, &mut replaced)
+            .unwrap();
+        assert_eq!(after, vec![AclGrant { account_id: 2, grants: earlier }]);
+        assert_eq!(replaced, vec![note.clone()]);
+
+        // The next sweep changes nothing, rather than removing that share
+        let swept = Lock { replaced: replaced.clone(), ..lock };
+        let mut again = Vec::new();
+        assert!(
+            merge_grants(&after, Collection::Mailbox, 5, false, Some(&swept), Some(&swept), 400, &mut again).is_none()
+        );
+        assert_eq!(again, vec![note]);
+    }
+
+    #[test]
+    fn the_timer_finds_the_next_end() {
+        let ends_at = |account_id, until| {
+            let mut d = delegate(account_id, Access::Read);
+            d.until = until;
+            d
+        };
+        let a = Lock { account_id: 10, ..lock_with(vec![ends_at(2, Some(500)), ends_at(3, None)], vec![]) };
+        let b = Lock { account_id: 11, ..lock_with(vec![ends_at(4, Some(300))], vec![]) };
+        let locks = vec![a, b];
+        assert_eq!(next_until(&locks, 100), Some(300));
+        assert_eq!(next_until(&locks, 300), Some(500));
+        assert_eq!(next_until(&locks, 500), None);
+        assert_eq!(ended_between(&locks, 100, 300).collect::<Vec<_>>(), vec![11]);
+        assert_eq!(ended_between(&locks, 300, 600).collect::<Vec<_>>(), vec![10]);
+        assert!(ended_between(&locks, 600, 900).next().is_none());
+    }
+
     #[test]
     fn expired_delegations_grant_nothing() {
         let lock = Lock {
diff --git a/crates/services/src/inbuxa_lock_expiry.rs b/crates/services/src/inbuxa_lock_expiry.rs
new file mode 100644
index 0000000..00f2b27
--- /dev/null
+++ b/crates/services/src/inbuxa_lock_expiry.rs
@@ -0,0 +1,71 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Ends a locked account's delegations at their `until` (AL-5), rather than
+//! at the next daily sweep. Each node sleeps until the soonest `until`, wakes
+//! early when a lock is written here, and checks at least hourly for locks
+//! written on other nodes. One node re-applies each lock; the others find it
+//! claimed.
+
+use common::{BuildServer, Inner, KV_LOCK_TASK, Server};
+use inbuxa_features::lock;
+use std::{sync::Arc, time::Duration};
+use store::write::now;
+
+/// The longest the timer sleeps, so an `until` set on another node is seen.
+const CEILING: u64 = 3600;
+
+pub fn spawn_lock_expiry(inner: Arc<Inner>) {
+    tokio::spawn(async move {
+        // Since boot: anything that ended while the server was down
+        let mut checked = 0;
+        loop {
+            let server = inner.build_server();
+            let now = now();
+            let wait = match lock::all(server.store()).await {
+                Ok(locks) => {
+                    for account_id in lock::ended_between(&locks, checked, now).collect::<Vec<_>>()
+                    {
+                        end_delegations(&server, account_id).await;
+                    }
+                    checked = now;
+                    lock::next_until(&locks, now)
+                        .map_or(CEILING, |until| (until - now).min(CEILING))
+                }
+                Err(err) => {
+                    trc::error!(err.details("Failed to read account locks for their end dates"));
+                    60
+                }
+            };
+            tokio::select! {
+                _ = tokio::time::sleep(Duration::from_secs(wait.max(1))) => {}
+                _ = lock::UNTIL_CHANGED.notified() => {}
+            }
+        }
+    });
+}
+
+async fn end_delegations(server: &Server, account_id: u32) {
+    let key = [b"lock-until:".as_slice(), &account_id.to_be_bytes()].concat();
+    match server
+        .in_memory_store()
+        .try_lock(KV_LOCK_TASK, &key, 60)
+        .await
+    {
+        Ok(true) => {
+            if let Err(err) = email::inbuxa_lock::reconcile(server, account_id).await {
+                trc::error!(
+                    err.account_id(account_id)
+                        .details("Failed to end a delegation at its date")
+                );
+            }
+        }
+        Ok(false) => {}
+        Err(err) => {
+            trc::error!(err.details("Failed to claim a delegation's end"));
+        }
+    }
+}
diff --git a/crates/services/src/lib.rs b/crates/services/src/lib.rs
index 682247f..c1e76d9 100644
--- a/crates/services/src/lib.rs
+++ b/crates/services/src/lib.rs
@@ -23,6 +23,8 @@ use std::sync::Arc;
 use crate::task_manager::{manager::spawn_task_manager, scheduler::spawn_task_scheduler};
 
 pub mod broadcast;
+// inbuxa: AL-5, delegations end at their date
+pub mod inbuxa_lock_expiry;
 pub mod state_manager;
 pub mod task_manager;
 
@@ -65,6 +67,9 @@ impl SpawnServices for IpcReceivers {
             // Spawn task manager
             spawn_task_manager(inner.clone());
 
+            // inbuxa: AL-5, end delegations at their `until`
+            inbuxa_lock_expiry::spawn_lock_expiry(inner.clone());
+
             // Spawn task scheduler
             spawn_task_scheduler(inner);
         }
diff --git a/tests/src/system/account_lock.rs b/tests/src/system/account_lock.rs
index 316dd15..40067d0 100644
--- a/tests/src/system/account_lock.rs
+++ b/tests/src/system/account_lock.rs
@@ -313,6 +313,39 @@ pub async fn test(test: &mut TestServer) {
         "AL-4: the rejected message wasn't kept: {kept}"
     );
 
+    // AL-5: a delegation ends at its `until`, not at the next daily sweep
+    let soon = store::write::now() + 3;
+    let response = admin
+        .lock_set(json!({"reason": "Handover ends shortly",
+            "update": {owner_id.as_str(): {"delegates": [
+            {"accountId": delegate.id_string(), "access": "organize",
+             "until": chrono::DateTime::from_timestamp(soon as i64, 0).unwrap().to_rfc3339_opts(chrono::SecondsFormat::Secs, true)}]}}}))
+        .await;
+    assert!(
+        response["updated"].get(owner_id.as_str()).is_some(),
+        "AL-5: {response}"
+    );
+    let (_, before) = delegate
+        .call("Mailbox/get", json!({"accountId": owner_id, "ids": null}))
+        .await;
+    assert!(
+        before["list"].as_array().is_some_and(|l| !l.is_empty()),
+        "AL-5: the delegate lost the account before its end: {before}"
+    );
+    tokio::time::sleep(Duration::from_secs(6)).await;
+    let session = delegate.jmap_session_object().await.0;
+    assert!(
+        session["accounts"].get(owner_id.as_str()).is_none(),
+        "AL-5: the delegation outlived its end in the session: {session}"
+    );
+    let (_, after) = delegate
+        .call("Mailbox/get", json!({"accountId": owner_id, "ids": null}))
+        .await;
+    assert!(
+        after["list"].as_array().is_none_or(|l| l.is_empty()),
+        "AL-5: the delegate still reaches the folders after its end: {after}"
+    );
+
     // AL-10: unlocking needs a reason, then restores everything
     let response = admin
         .lock_set(json!({"destroy": [owner_id]}))