diff --git a/packages/backend/src/actors/FingerprintStore.ts b/packages/backend/src/actors/FingerprintStore.ts
index 9dc4f4b8..3a43a07a 100644
--- a/packages/backend/src/actors/FingerprintStore.ts
+++ b/packages/backend/src/actors/FingerprintStore.ts
@@ -50,14 +50,11 @@ export class FingerprintStore extends SubscribableActor<Fingerprint, Fingerprint
 		}
 		const result = await FingerprintStoreMessages.match<Promise<FingerprintStoreResult>>(message, {
 			StoreFingerprint: async fingerprint => {
-				this.state = await create(this.state, async draft => {
-					const currentFingerprint = (await this.getEntity(fingerprint.uid)).orElse({} as Fingerprint);
-					fingerprint.updated = toTimestamp();
-					const newFingerprint = { ...currentFingerprint, ...fingerprint };
-					draft.cache.set(fingerprint.uid, newFingerprint);
-					logger.debug(`Storing new fingerprint ${JSON.stringify(newFingerprint)}`);
-					this.storeEntity(newFingerprint);
-				});
+				const currentFingerprint = (await this.getEntity(fingerprint.uid)).orElse({} as Fingerprint);
+				fingerprint.updated = toTimestamp();
+				const newFingerprint = { ...currentFingerprint, ...fingerprint };
+				logger.debug(`Storing new fingerprint ${JSON.stringify(newFingerprint)}`);
+				await this.storeEntity(newFingerprint);
 				return unit();
 			},
 			Get: async id => {
@@ -66,49 +63,42 @@ export class FingerprintStore extends SubscribableActor<Fingerprint, Fingerprint
 				return Promise.resolve(retVal)
 			},
 			Block: async id => {
-				const mbFingerprint = await this.getEntity(id)
-				const {uid} = await this.ask<UserStoreMessage, User>("actors://recapp-backend/UserStore", UserStoreMessages.GetByFingerprint(id));
-				return mbFingerprint.match<Unit|Error>(
-					fp => {
-						this.storeEntity({...fp, blocked: true});
-						this.updateSubscribers({...fp, blocked: true})
-						if (uid)
-							this.send("actors://recapp-backend/UserStore", UserStoreMessages.Update({ uid, active: false }));
-						return unit();
-					},
-					() => {
-						return new Error(`Unknown fingerprint id ${id}`);
-					}
-				)
+				const fp = (await this.getEntity(id)).orUndefined();
+				if (!fp) {
+					return new Error(`Unknown fingerprint id ${id}`);
+				}
+				const { uid } = await this.ask<UserStoreMessage, User>("actors://recapp-backend/UserStore", UserStoreMessages.GetByFingerprint(id));
+				const updated = { ...fp, blocked: true };
+				await this.storeEntity(updated);
+				this.updateSubscribers(updated);
+				if (uid) {
+					this.send("actors://recapp-backend/UserStore", UserStoreMessages.Update({ uid, active: false }));
+				}
+				return unit();
 			},
 			Unblock: async id => {
-				const mbFingerprint = await this.getEntity(id)
-				const {uid} = await this.ask<UserStoreMessage, User>("actors://recapp-backend/UserStore", UserStoreMessages.GetByFingerprint(id));
-				return mbFingerprint.match<Unit|Error>(
-					fp => {
-						this.storeEntity({...fp, blocked: false});
-						this.updateSubscribers({...fp, blocked: false})
-						if (uid)
-							this.send("actors://recapp-backend/UserStore", UserStoreMessages.Update({ uid, active: true }));
-						return unit();
-					},
-					() => {
-						return new Error(`Unknown fingerprint id ${id}`);
-					}
-				)
+				const fp = (await this.getEntity(id)).orUndefined();
+				if (!fp) {
+					return new Error(`Unknown fingerprint id ${id}`);
+				}
+				const { uid } = await this.ask<UserStoreMessage, User>("actors://recapp-backend/UserStore", UserStoreMessages.GetByFingerprint(id));
+				const updated = { ...fp, blocked: false };
+				await this.storeEntity(updated);
+				this.updateSubscribers(updated);
+				if (uid) {
+					this.send("actors://recapp-backend/UserStore", UserStoreMessages.Update({ uid, active: true }));
+				}
+				return unit();
 			},
 			IncreaseCount: async ({fingerprint, userUid, initialQuiz}) => {
-				const mbFingerprint = await this.getEntity(fingerprint)
-				return mbFingerprint.match<Unit|Error>(
-					fp => {
-						this.storeEntity({...fp, usageCount: fp.usageCount + 1, lastSeen: toTimestamp(), userUid, initialQuiz: initialQuiz ?? fp.initialQuiz});
-						this.updateSubscribers({...fp, usageCount: fp.usageCount + 1, lastSeen: toTimestamp(), userUid, initialQuiz: initialQuiz ?? fp.initialQuiz})
-						return unit();
-					},
-					() => {
-						return new Error(`Unknown fingerprint id ${fingerprint}`);
-					}
-				)
+				const fp = (await this.getEntity(fingerprint)).orUndefined();
+				if (!fp) {
+					return new Error(`Unknown fingerprint id ${fingerprint}`);
+				}
+				const updated = { ...fp, usageCount: fp.usageCount + 1, lastSeen: toTimestamp(), userUid, initialQuiz: initialQuiz ?? fp.initialQuiz };
+				await this.storeEntity(updated);
+				this.updateSubscribers(updated);
+				return unit();
 			},
 			GetMostRecent: async () => {
 				const db = await this.connector.db();
diff --git a/packages/backend/src/actors/SessionStore.ts b/packages/backend/src/actors/SessionStore.ts
index cdf6edb1..8eaebe99 100644
--- a/packages/backend/src/actors/SessionStore.ts
+++ b/packages/backend/src/actors/SessionStore.ts
@@ -47,16 +47,16 @@ export class SessionStore extends StoringActor<Session, SessionStoreMessage, Ses
 	public async receive(from: ActorRef, message: SessionStoreMessage): Promise<SessionStoreResult> {
 		const result = await SessionStoreMessages.match<Promise<SessionStoreResult>>(message, {
 			StoreSession: async session => {
-				this.state = await create(this.state, async draft => {
-					const currentSession = (await this.getEntity(session.uid)).orElse({} as Session);
+				const currentSession = (await this.getEntity(session.uid)).orElse({} as Session);
+				session.updated = toTimestamp();
+				const newSession = { ...currentSession, ...session };
+				this.state = create(this.state, draft => {
 					if (session.actorSystem) {
 						draft.clientIndex.set(session.actorSystem, session.uid);
 					}
-					session.updated = toTimestamp();
-					const newSession = { ...currentSession, ...session };
 					draft.cache.set(session.uid, newSession);
-					this.storeEntity(newSession);
 				});
+				await this.storeEntity(newSession);
 				return unit();
 			},
 			CheckSession: async userId => {
diff --git a/packages/backend/src/actors/StatisticsActor.ts b/packages/backend/src/actors/StatisticsActor.ts
index deb8d1de..14f3ede5 100644
--- a/packages/backend/src/actors/StatisticsActor.ts
+++ b/packages/backend/src/actors/StatisticsActor.ts
@@ -243,7 +243,7 @@ export class StatisticsActor extends SubscribableActor<
 					);
 					// console.log("STATS", stats);
 					this.logger.info(`STATS stored quizId=${String(this.uid)}`);
-					this.storeEntity(stats);
+					await this.storeEntity(stats);
 					for (const [subscriber] of this.state.collectionSubscribers) {
 						this.send(subscriber, new StatisticsUpdateMessage(stats));
 					}
diff --git a/packages/backend/src/actors/UserStore.ts b/packages/backend/src/actors/UserStore.ts
index 82bc609e..478d9eca 100644
--- a/packages/backend/src/actors/UserStore.ts
+++ b/packages/backend/src/actors/UserStore.ts
@@ -353,26 +353,6 @@ export class UserStore extends SubscribableActor<User, UserStoreMessage, ResultT
 			newUser.updated = toTimestamp();
 			draft.cache.set(userToStore.uid, newUser);
 
-			// If the role has changed, also update the session store
-			if (oldUser.role !== newUser.role) {
-				(
-					this.ask(
-						createActorUri("SessionStore"),
-						SessionStoreMessages.GetSessionForUserId(newUser.uid)
-					) as Promise<Session>
-				)
-					.then((session: Session) => {
-						session.role = newUser.role;
-						this.send(createActorUri("SessionStore"), SessionStoreMessages.StoreSession(session));
-					})
-					.catch((e: unknown) => {
-						this.logger.error(
-							`Failed to update session role for user ${String(newUser.uid)}: ` +
-							`${e instanceof Error ? e.stack : String(e)}`
-						);
-					});
-			}
-
 			for (const [subscriber, subscription] of this.state.collectionSubscribers) {
 				this.send(
 					subscriber,
@@ -389,8 +369,30 @@ export class UserStore extends SubscribableActor<User, UserStoreMessage, ResultT
 		});
 		// console.log("Updated user", newUser);
 		this.logger.info(`USERSTORE updated user uid=${String((newUser as any)?.uid ?? "?")}`);
-		return this.storeEntity(newUser)
+		const storeResult = await this.storeEntity(newUser)
 			.then(() => newUser)
 			.catch(error => error as Error);
+		if (!(storeResult instanceof Error) && oldUser.role !== newUser.role) {
+			try {
+				const sessionOrError = await this.ask(
+					createActorUri("SessionStore"),
+					SessionStoreMessages.GetSessionForUserId(newUser.uid)
+				);
+				if (!(sessionOrError instanceof Error)) {
+					const session = sessionOrError as Session;
+					session.role = newUser.role;
+					await this.ask(
+						createActorUri("SessionStore"),
+						SessionStoreMessages.StoreSession(session)
+					);
+				}
+			} catch (e: unknown) {
+				this.logger.error(
+					`Failed to update session role for user ${String(newUser.uid)}: ` +
+					`${e instanceof Error ? e.stack : String(e)}`
+				);
+			}
+		}
+		return storeResult;
 	};
 }
diff --git a/packages/frontend/src/actors/CurrentQuizActor.ts b/packages/frontend/src/actors/CurrentQuizActor.ts
index 45dea603..ccfef043 100644
--- a/packages/frontend/src/actors/CurrentQuizActor.ts
+++ b/packages/frontend/src/actors/CurrentQuizActor.ts
@@ -598,7 +598,7 @@ export class CurrentQuizActor extends StatefulActor<MessageType, Unit | boolean
 								g.questions = g.questions.filter(q => q !== id);
 								return g;
 							});
-							await this.send(
+							await this.ask(
 								actorUris.QuizActor,
 								QuizActorMessages.Update({ uid: this.state.quiz.uid, groups })
 							);
diff --git a/packages/frontend/src/actors/SharingActor.ts b/packages/frontend/src/actors/SharingActor.ts
index 66ef9bd2..94196251 100644
--- a/packages/frontend/src/actors/SharingActor.ts
+++ b/packages/frontend/src/actors/SharingActor.ts
@@ -76,6 +76,11 @@ export class SharingActor extends StatefulActor<SharingMessage, Unit, SharingSta
 								draft.errors.push({ id: toId(v4()), queryNotFound: query });
 							});
 						}
+					})
+					.catch(() => {
+						this.updateState(draft => {
+							draft.errors.push({ id: toId(v4()), queryNotFound: query });
+						});
 					});
 			},
 			Clear: () => {
diff --git a/packages/frontend/src/components/modals/ChangeNicknameModal.tsx b/packages/frontend/src/components/modals/ChangeNicknameModal.tsx
index 3b526609..65ff6e2f 100644
--- a/packages/frontend/src/components/modals/ChangeNicknameModal.tsx
+++ b/packages/frontend/src/components/modals/ChangeNicknameModal.tsx
@@ -33,6 +33,7 @@ export const ChangeNicknameModal: React.FC<Props> = ({ show, defaultValue, onClo
                 s
                     .ask("actors://recapp-backend/UserStore", UserStoreMessages.IsNicknameUnique(newValue))
                     .then(result => !result && setError(i18n._("error-nickname-already-used")))
+                    .catch(() => { /* network error — skip uniqueness check */ })
             );
         }
     };