diff --git a/src/main/java/org/thoughtcrime/securesms/ConversationActivity.java b/src/main/java/org/thoughtcrime/securesms/ConversationActivity.java
index dcc94c486..73d14a578 100644
--- a/src/main/java/org/thoughtcrime/securesms/ConversationActivity.java
+++ b/src/main/java/org/thoughtcrime/securesms/ConversationActivity.java
@@ -325,6 +325,11 @@ protected void onNewIntent(Intent intent) {
       return;
     }
 
+    if (intent.getIntExtra(CHAT_ID_EXTRA, DcChat.DC_CHAT_NO_CHAT) == DcChat.DC_CHAT_NO_CHAT) {
+      Log.w(TAG, "onNewIntent: ignoring intent with invalid chat ID");
+      return;
+    }
+
     if (!Util.isEmpty(composeText) || attachmentManager.isAttachmentPresent()) {
       processComposeControls(ACTION_SAVE_DRAFT);
       attachmentManager.clear(glideRequests, false);
@@ -1116,8 +1121,11 @@ private void initializeResources() {
       initializeBackground();
     }
     chatId = getIntent().getIntExtra(CHAT_ID_EXTRA, -1);
-    if (chatId == DcChat.DC_CHAT_NO_CHAT)
-      throw new IllegalStateException("can't display a conversation for no chat.");
+    if (chatId == DcChat.DC_CHAT_NO_CHAT) {
+      Log.e(TAG, "initializeResources: invalid chat ID " + chatId + ", finishing activity");
+      finish();
+      return;
+    }
     dcChat = DcHelper.getContext(context).getChat(chatId);
     recipient = new Recipient(this, dcChat);
     glideRequests = GlideApp.with(this);
diff --git a/src/main/java/org/thoughtcrime/securesms/ConversationFragment.java b/src/main/java/org/thoughtcrime/securesms/ConversationFragment.java
index 46e5de0b1..3929174dc 100644
--- a/src/main/java/org/thoughtcrime/securesms/ConversationFragment.java
+++ b/src/main/java/org/thoughtcrime/securesms/ConversationFragment.java
@@ -646,6 +646,10 @@ private void handleReplyMessagePrivately(final DcMsg msg) {
     if (getActivity() != null) {
       DcContext dcContext = DcHelper.getContext(getActivity());
       int privateChatId = dcContext.createChatByContactId(msg.getFromId());
+      if (privateChatId == 0) {
+        Log.w(TAG, "createChatByContactId returned 0, cannot reply privately");
+        return;
+      }
       DcMsg replyMsg = new DcMsg(dcContext, DcMsg.DC_MSG_TEXT);
       replyMsg.setQuote(msg);
       dcContext.setDraft(privateChatId, replyMsg);
diff --git a/src/main/java/org/thoughtcrime/securesms/ShareActivity.java b/src/main/java/org/thoughtcrime/securesms/ShareActivity.java
index a9fb0ccc3..bd2013b16 100644
--- a/src/main/java/org/thoughtcrime/securesms/ShareActivity.java
+++ b/src/main/java/org/thoughtcrime/securesms/ShareActivity.java
@@ -268,7 +268,7 @@ private void handleResolvedMedia(Intent intent) {
       accId = dcContext.getAccountId();
     }
     Intent composeIntent;
-    if (accId != -1 && chatId != -1) {
+    if (accId != -1 && chatId > 0) {
       composeIntent = getBaseShareIntent(ConversationActivity.class);
       composeIntent.putExtra(ConversationActivity.CHAT_ID_EXTRA, chatId);
       composeIntent.putExtra(ConversationActivity.ACCOUNT_ID_EXTRA, accId);
diff --git a/src/main/java/org/thoughtcrime/securesms/contacts/NewContactActivity.java b/src/main/java/org/thoughtcrime/securesms/contacts/NewContactActivity.java
index 5fb33d4dd..759f7b29e 100644
--- a/src/main/java/org/thoughtcrime/securesms/contacts/NewContactActivity.java
+++ b/src/main/java/org/thoughtcrime/securesms/contacts/NewContactActivity.java
@@ -88,9 +88,11 @@ public boolean onOptionsItemSelected(@NonNull MenuItem item) {
         setResult(RESULT_OK, intent);
       } else {
         int chatId = dcContext.createChatByContactId(contactId);
-        Intent intent = new Intent(this, ConversationActivity.class);
-        intent.putExtra(ConversationActivity.CHAT_ID_EXTRA, chatId);
-        startActivity(intent);
+        if (chatId != 0) {
+          Intent intent = new Intent(this, ConversationActivity.class);
+          intent.putExtra(ConversationActivity.CHAT_ID_EXTRA, chatId);
+          startActivity(intent);
+        }
       }
       finish();
       return true;
diff --git a/src/main/java/org/thoughtcrime/securesms/qr/QrCodeHandler.java b/src/main/java/org/thoughtcrime/securesms/qr/QrCodeHandler.java
index 2b8af6bbf..f9aabea23 100644
--- a/src/main/java/org/thoughtcrime/securesms/qr/QrCodeHandler.java
+++ b/src/main/java/org/thoughtcrime/securesms/qr/QrCodeHandler.java
@@ -324,6 +324,10 @@ private void showFingerprintOrQrSuccess(
         R.string.start_chat,
         (dialogInterface, i) -> {
           int chatId = dcContext.createChatByContactId(qrParsed.getId());
+          if (chatId == 0) {
+            Log.w(TAG, "createChatByContactId returned 0, ignoring");
+            return;
+          }
           Intent intent = new Intent(activity, ConversationActivity.class);
           intent.putExtra(ConversationActivity.CHAT_ID_EXTRA, chatId);
           if (qrParsed.getText1Meaning() == DcLot.DC_TEXT1_DRAFT) {