diff --git a/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderRecurrenceTest.java b/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderRecurrenceTest.java
index 7032cbfb0..ffe5f29af 100644
--- a/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderRecurrenceTest.java
+++ b/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderRecurrenceTest.java
@@ -200,6 +200,70 @@ public void testRRule() throws InvalidRecurrenceRuleException
     }
 
 
+
+    /**
+     * Test if instances of a task with an all-day DTSTART, DUE and an RRULE.
+     */
+    @Test
+    public void testAllDayRRule() throws InvalidRecurrenceRuleException
+    {
+        RowSnapshot<TaskLists> taskList = new VirtualRowSnapshot<>(new LocalTaskListsTable(mAuthority));
+        Table<Instances> instancesTable = new InstanceTable(mAuthority);
+        RowSnapshot<Tasks> task = new VirtualRowSnapshot<>(new TaskListScoped(taskList, new TasksTable(mAuthority)));
+
+        Duration days = new Duration(1, 2, 0);
+        DateTime start = DateTime.parse("20180104");
+        DateTime due = start.addDuration(days);
+        DateTime localStart = start;
+
+        Duration day = new Duration(1, 1, 0);
+
+        DateTime second = localStart.addDuration(day);
+        DateTime third = second.addDuration(day);
+        DateTime fourth = third.addDuration(day);
+        DateTime fifth = fourth.addDuration(day);
+
+        DateTime localDue = due;
+
+        assertThat(new Seq<>(
+                        new Put<>(taskList, new EmptyRowData<>()),
+                        new Put<>(task,
+                                new Composite<>(
+                                        new TimeData<>(start, due),
+                                        new RRuleTaskData(new RecurrenceRule("FREQ=DAILY;COUNT=5", RecurrenceRule.RfcMode.RFC2445_LAX))))
+
+                ), resultsIn(mClient,
+                new Assert<>(task,
+                        new Composite<>(
+                                new TimeData<>(start, due),
+                                new CharSequenceRowData<>(Tasks.RRULE, "FREQ=DAILY;COUNT=5"))),
+//                new Counted<>(5, new AssertRelated<>(instancesTable, Instances.TASK_ID, task)),
+                new Counted<>(1, new AssertRelated<>(instancesTable, Instances.TASK_ID, task)),
+                // 1st instance:
+                new AssertRelated<>(instancesTable, Instances.TASK_ID, task,
+                        new InstanceTestData(localStart, localDue, new Present<>(start), 0),
+                        new EqArg(Instances.INSTANCE_ORIGINAL_TIME, start.getTimestamp()))/*,
+                // 2nd instance:
+                new AssertRelated<>(instancesTable, Instances.TASK_ID, task,
+                        new InstanceTestData(second, second.addDuration(hour), new Present<>(second), 1),
+                        new EqArg(Instances.INSTANCE_ORIGINAL_TIME, second.getTimestamp())),
+                // 3rd instance:
+                new AssertRelated<>(instancesTable, Instances.TASK_ID, task,
+                        new InstanceTestData(third, third.addDuration(hour), new Present<>(third), 2),
+                        new EqArg(Instances.INSTANCE_ORIGINAL_TIME, third.getTimestamp())),
+                // 4th instance:
+                new AssertRelated<>(instancesTable, Instances.TASK_ID, task,
+                        new InstanceTestData(fourth, fourth.addDuration(hour), new Present<>(fourth), 3),
+                        new EqArg(Instances.INSTANCE_ORIGINAL_TIME, fourth.getTimestamp())),
+                // 5th instance:
+                new AssertRelated<>(instancesTable, Instances.TASK_ID, task,
+                        new InstanceTestData(fifth, fifth.addDuration(hour), new Present<>(fifth), 4),
+                        new EqArg(Instances.INSTANCE_ORIGINAL_TIME, fifth.getTimestamp())) */)
+        );
+    }
+
+
+
     /**
      * Test if instances of a task with a DUE and an RRULE but no DTSTART.
      */
diff --git a/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderTest.java b/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderTest.java
index e75914451..911f43d53 100644
--- a/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderTest.java
+++ b/opentasks-provider/src/androidTest/java/org/dmfs/provider/tasks/TaskProviderTest.java
@@ -335,6 +335,40 @@ public void testInsertTaskWithStartAndDue()
     }
 
 
+
+    /**
+     * Create task with start and due, check datetime values including generated duration.
+     */
+    @Test
+    public void testInsertTaskWithAlldayStartAndDue()
+    {
+        RowSnapshot<TaskLists> taskList = new VirtualRowSnapshot<>(new LocalTaskListsTable(mAuthority));
+        RowSnapshot<Tasks> task = new VirtualRowSnapshot<>(new TaskListScoped(taskList, new TasksTable(mAuthority)));
+
+        DateTime start = DateTime.now().toAllDay();
+        DateTime due = start.addDuration(new Duration(1, 2, 0));
+
+        assertThat(new Seq<>(
+                new Put<>(taskList, new EmptyRowData<TaskLists>()),
+                new Put<>(task, new TimeData<>(start, due))
+
+        ), resultsIn(mClient,
+                new Assert<>(task, new Composite<>(
+                        new TimeData<>(start, due),
+                        new VersionData(0))),
+                new AssertRelated<>(
+                        new InstanceTable(mAuthority), Instances.TASK_ID, task,
+                        new Composite<Instances>(
+                                new InstanceTestData(
+                                        start,
+                                        due,
+                                        absent(),
+                                        0),
+                                new CharSequenceRowData<>(Tasks.TZ, "UTC"))
+                )));
+    }
+
+
     /**
      * Create task with start and due, check datetime and INSTANCE_STATUS values after updating the status.
      */
diff --git a/opentasks-provider/src/main/java/org/dmfs/provider/tasks/utils/InstanceValuesIterable.java b/opentasks-provider/src/main/java/org/dmfs/provider/tasks/utils/InstanceValuesIterable.java
index f8317d8fe..3613a83f0 100644
--- a/opentasks-provider/src/main/java/org/dmfs/provider/tasks/utils/InstanceValuesIterable.java
+++ b/opentasks-provider/src/main/java/org/dmfs/provider/tasks/utils/InstanceValuesIterable.java
@@ -91,7 +91,7 @@ public Iterator<Single<ContentValues>> iterator()
 
             return new Mapped<>(dateTime -> new Distant(mTaskAdapter.valueOf(TaskAdapter.IS_CLOSED) ? -1 : 0,
                     new Overridden(new Present<>(dateTime),
-                            new Enduring(new DueDated(new Zipped<>(new Present<>(dateTime), effectiveDuration, DateTime::addDuration),
+                            new Enduring(new DueDated(new Zipped<>(new Present<>(dateTime), effectiveDuration, this::addDuration),
                                     new StartDated(new Present<>(dateTime), new VanillaInstanceData()))))),
                     new TaskInstanceIterable(mTaskAdapter).iterator());
         }
@@ -104,4 +104,14 @@ public Iterator<Single<ContentValues>> iterator()
 
     }
 
+
+    private DateTime addDuration(DateTime dt, Duration dur)
+    {
+        if (dt.isAllDay() && dur.getSecondsOfDay() != 0)
+        {
+            dur = new Duration(1, dur.getWeeks() * 7 + dur.getDays() + dur.getSecondsOfDay() / (3600 * 24), 0);
+        }
+        return dt.addDuration(dur);
+    }
+
 }