diff --git a/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/LiveDataObservable.kt b/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/LiveDataObservable.kt
index 7958d3efa1..302e775056 100644
--- a/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/LiveDataObservable.kt
+++ b/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/LiveDataObservable.kt
@@ -20,6 +20,7 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
 import io.reactivex.Observable
 import io.reactivex.android.MainThreadDisposable
+import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.schedulers.Schedulers
 
 private class LiveDataObservable<T>(
@@ -57,6 +58,14 @@ private class LiveDataObservable<T>(
     }
 }
 
-fun <T> LiveData<T>.asObservable(): Observable<T> {
+internal fun <T> LiveData<T>.asObservable(): Observable<T> {
     return LiveDataObservable(this).observeOn(Schedulers.computation())
 }
+
+internal fun <T> Observable<T>.startWithCallable(supplier: () -> T): Observable<T> {
+    val startObservable = Observable
+            .fromCallable(supplier)
+            .subscribeOn(Schedulers.io())
+            .observeOn(AndroidSchedulers.mainThread())
+    return startWith(startObservable)
+}
diff --git a/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxRoom.kt b/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxRoom.kt
index 9491a69ef1..ef55b090b7 100644
--- a/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxRoom.kt
+++ b/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxRoom.kt
@@ -35,27 +35,37 @@ class RxRoom(private val room: Room) {
 
     fun liveRoomSummary(): Observable<Optional<RoomSummary>> {
         return room.getRoomSummaryLive().asObservable()
-                .startWith(room.roomSummary().toOptional())
+                .startWithCallable {
+                    room.roomSummary().toOptional()
+                }
     }
 
     fun liveRoomMembers(queryParams: RoomMemberQueryParams): Observable<List<RoomMemberSummary>> {
         return room.getRoomMembersLive(queryParams).asObservable()
-                .startWith(room.getRoomMembers(queryParams))
+                .startWithCallable {
+                    room.getRoomMembers(queryParams)
+                }
     }
 
     fun liveAnnotationSummary(eventId: String): Observable<Optional<EventAnnotationsSummary>> {
         return room.getEventAnnotationsSummaryLive(eventId).asObservable()
-                .startWith(room.getEventAnnotationsSummary(eventId).toOptional())
+                .startWithCallable {
+                    room.getEventAnnotationsSummary(eventId).toOptional()
+                }
     }
 
     fun liveTimelineEvent(eventId: String): Observable<Optional<TimelineEvent>> {
         return room.getTimeLineEventLive(eventId).asObservable()
-                .startWith(room.getTimeLineEvent(eventId).toOptional())
+                .startWithCallable {
+                    room.getTimeLineEvent(eventId).toOptional()
+                }
     }
 
     fun liveStateEvent(eventType: String): Observable<Optional<Event>> {
         return room.getStateEventLive(eventType).asObservable()
-                .startWith(room.getStateEvent(eventType).toOptional())
+                .startWithCallable {
+                    room.getStateEvent(eventType).toOptional()
+                }
     }
 
     fun liveReadMarker(): Observable<Optional<String>> {
diff --git a/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxSession.kt b/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxSession.kt
index 406e274258..edba4ca9bf 100644
--- a/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxSession.kt
+++ b/matrix-sdk-android-rx/src/main/java/im/vector/matrix/rx/RxSession.kt
@@ -36,17 +36,23 @@ class RxSession(private val session: Session) {
 
     fun liveRoomSummaries(queryParams: RoomSummaryQueryParams): Observable<List<RoomSummary>> {
         return session.getRoomSummariesLive(queryParams).asObservable()
-                .startWith(session.getRoomSummaries(queryParams))
+                .startWithCallable {
+                    session.getRoomSummaries(queryParams)
+                }
     }
 
     fun liveGroupSummaries(queryParams: GroupSummaryQueryParams): Observable<List<GroupSummary>> {
         return session.getGroupSummariesLive(queryParams).asObservable()
-                .startWith(session.getGroupSummaries(queryParams))
+                .startWithCallable {
+                    session.getGroupSummaries(queryParams)
+                }
     }
 
     fun liveBreadcrumbs(): Observable<List<RoomSummary>> {
         return session.getBreadcrumbsLive().asObservable()
-                .startWith(session.getBreadcrumbs())
+                .startWithCallable {
+                    session.getBreadcrumbs()
+                }
     }
 
     fun liveSyncState(): Observable<SyncState> {
@@ -59,7 +65,9 @@ class RxSession(private val session: Session) {
 
     fun liveUser(userId: String): Observable<Optional<User>> {
         return session.getUserLive(userId).asObservable()
-                .startWith(session.getUser(userId).toOptional())
+                .startWithCallable {
+                    session.getUser(userId).toOptional()
+                }
     }
 
     fun liveUsers(): Observable<List<User>> {