diff --git a/src/cheogram/java/eu/siacs/conversations/services/QuickConversationsService.java b/src/cheogram/java/eu/siacs/conversations/services/QuickConversationsService.java
index 2f939adc05786fa15baa1371a05c1d49325e735e..9920ba2aabb75b7fa1b9bed4cc3535ed86d09550 100644
--- a/src/cheogram/java/eu/siacs/conversations/services/QuickConversationsService.java
+++ b/src/cheogram/java/eu/siacs/conversations/services/QuickConversationsService.java
@@ -130,7 +130,7 @@ public class QuickConversationsService extends AbstractQuickConversationsService
         mRunningSyncJobs.incrementAndGet();
 
         mLastSyncAttempt.put(account.getUuid(), Attempt.create(hash));
-        final List<Contact> withSystemAccounts = account.getRoster().getWithSystemAccounts(PhoneNumberContact.class);
+        final List<Contact> withSystemAccounts = new ArrayList<>(account.getRoster().getWithSystemAccounts(PhoneNumberContact.class));
         for (Map.Entry<String, PhoneNumberContact> item : contacts.entrySet()) {
             PhoneNumberContact phoneContact = item.getValue();
             for(String gateway : gateways) {