diff --git a/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailViewModel.kt b/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailViewModel.kt
index e7a18753cd..614a75265d 100644
--- a/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailViewModel.kt
+++ b/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailViewModel.kt
@@ -819,9 +819,14 @@ class RoomDetailViewModel @AssistedInject constructor(@Assisted initialState: Ro
         if (events.isEmpty()) return UnreadState.Unknown
         val readMarkerIdSnapshot = roomSummary.readMarkerId ?: return UnreadState.Unknown
         val firstDisplayableEventId = timeline.getFirstDisplayableEventId(readMarkerIdSnapshot)
-                ?: return UnreadState.ReadMarkerNotLoaded(readMarkerIdSnapshot)
         val firstDisplayableEventIndex = timeline.getIndexOfEvent(firstDisplayableEventId)
-                ?: return UnreadState.ReadMarkerNotLoaded(readMarkerIdSnapshot)
+        if (firstDisplayableEventId == null || firstDisplayableEventIndex == null) {
+            return if (timeline.isLive) {
+                UnreadState.ReadMarkerNotLoaded(readMarkerIdSnapshot)
+            } else {
+                UnreadState.Unknown
+            }
+        }
         for (i in (firstDisplayableEventIndex - 1) downTo 0) {
             val timelineEvent = events.getOrNull(i) ?: return UnreadState.Unknown
             val eventId = timelineEvent.root.eventId ?: return UnreadState.Unknown