diff --git a/changelog.d/6463.bugfix b/changelog.d/6463.bugfix
new file mode 100644
index 0000000000..63d66d018e
--- /dev/null
+++ b/changelog.d/6463.bugfix
@@ -0,0 +1 @@
+Fix crashes when opening Thread
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt
index d1eb8794bf..4eaac67e5a 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt
@@ -20,6 +20,7 @@ import io.realm.Realm
 import io.realm.RealmConfiguration
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.android.asCoroutineDispatcher
 import kotlinx.coroutines.cancelChildren
@@ -116,6 +117,7 @@ internal class DefaultTimeline(
     )
 
     private var strategy: LoadTimelineStrategy = buildStrategy(LoadTimelineStrategy.Mode.Live)
+    private var startTimelineJob: Job? = null
 
     override val isLive: Boolean
         get() = !getPaginationState(Timeline.Direction.FORWARDS).hasMoreToLoad
@@ -143,7 +145,7 @@ internal class DefaultTimeline(
         timelineScope.launch {
             loadRoomMembersIfNeeded()
         }
-        timelineScope.launch {
+        startTimelineJob = timelineScope.launch {
             sequencer.post {
                 if (isStarted.compareAndSet(false, true)) {
                     isFromThreadTimeline = rootThreadEventId != null
@@ -174,8 +176,10 @@ internal class DefaultTimeline(
 
     override fun restartWithEventId(eventId: String?) {
         timelineScope.launch {
-            openAround(eventId, rootThreadEventId)
-            postSnapshot()
+            sequencer.post {
+                openAround(eventId, rootThreadEventId)
+                postSnapshot()
+            }
         }
     }
 
@@ -185,6 +189,7 @@ internal class DefaultTimeline(
 
     override fun paginate(direction: Timeline.Direction, count: Int) {
         timelineScope.launch {
+            startTimelineJob?.join()
             val postSnapshot = loadMore(count, direction, fetchOnServerIfNeeded = true)
             if (postSnapshot) {
                 postSnapshot()
@@ -193,6 +198,7 @@ internal class DefaultTimeline(
     }
 
     override suspend fun awaitPaginate(direction: Timeline.Direction, count: Int): List<TimelineEvent> {
+        startTimelineJob?.join()
         withContext(timelineDispatcher) {
             loadMore(count, direction, fetchOnServerIfNeeded = true)
         }
@@ -279,6 +285,7 @@ internal class DefaultTimeline(
                 direction = Timeline.Direction.BACKWARDS,
                 fetchOnServerIfNeeded = false
         )
+
         Timber.v("$baseLogMessage finished")
     }
 
@@ -312,9 +319,11 @@ internal class DefaultTimeline(
 
     private fun onLimitedTimeline() {
         timelineScope.launch {
-            initPaginationStates(null)
-            loadMore(settings.initialSize, Timeline.Direction.BACKWARDS, false)
-            postSnapshot()
+            sequencer.post {
+                initPaginationStates(null)
+                loadMore(settings.initialSize, Timeline.Direction.BACKWARDS, false)
+                postSnapshot()
+            }
         }
     }
 
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/LoadTimelineStrategy.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/LoadTimelineStrategy.kt
index c5d4d346fd..2d50fcb67a 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/LoadTimelineStrategy.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/LoadTimelineStrategy.kt
@@ -32,6 +32,7 @@ import org.matrix.android.sdk.api.session.room.timeline.Timeline
 import org.matrix.android.sdk.api.session.room.timeline.TimelineEvent
 import org.matrix.android.sdk.api.session.room.timeline.TimelineSettings
 import org.matrix.android.sdk.api.settings.LightweightSettingsStorage
+import org.matrix.android.sdk.internal.database.awaitTransaction
 import org.matrix.android.sdk.internal.database.helper.addIfNecessary
 import org.matrix.android.sdk.internal.database.mapper.TimelineEventMapper
 import org.matrix.android.sdk.internal.database.model.ChunkEntity
@@ -265,7 +266,7 @@ internal class LoadTimelineStrategy constructor(
         }
     }
 
-    private fun getChunkEntity(realm: Realm): RealmResults<ChunkEntity> {
+    private suspend fun getChunkEntity(realm: Realm): RealmResults<ChunkEntity> {
         return when (mode) {
             is Mode.Live -> {
                 ChunkEntity.where(realm, roomId)
@@ -289,8 +290,8 @@ internal class LoadTimelineStrategy constructor(
      * Clear any existing thread chunk entity and create a new one, with the
      * rootThreadEventId included.
      */
-    private fun recreateThreadChunkEntity(realm: Realm, rootThreadEventId: String) {
-        realm.executeTransaction {
+    private suspend fun recreateThreadChunkEntity(realm: Realm, rootThreadEventId: String) {
+        awaitTransaction(realm.configuration) {
             // Lets delete the chunk and start a new one
             ChunkEntity.findLastForwardChunkOfThread(it, roomId, rootThreadEventId)?.deleteAndClearThreadEvents()?.let {
                 Timber.i("###THREADS LoadTimelineStrategy [onStart] thread chunk cleared..")
@@ -309,8 +310,8 @@ internal class LoadTimelineStrategy constructor(
     /**
      * Clear any existing thread chunk.
      */
-    private fun clearThreadChunkEntity(realm: Realm, rootThreadEventId: String) {
-        realm.executeTransaction {
+    private suspend fun clearThreadChunkEntity(realm: Realm, rootThreadEventId: String) {
+        awaitTransaction(realm.configuration) {
             ChunkEntity.findLastForwardChunkOfThread(it, roomId, rootThreadEventId)?.deleteAndClearThreadEvents()?.let {
                 Timber.i("###THREADS LoadTimelineStrategy [onStop] thread chunk cleared..")
             }