diff --git a/FAQ.md b/FAQ.md
index b2a4212e10..8314b42c36 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -3419,6 +3419,7 @@ The resend menu item will be shown grayed (dimmed) if the message headers are no
 
 Remarks:
 
+* Messages to, CC or BCC *undisclosed-recipients:* cannot be resend
 * The original subject is sent as-is, unless it is being changed
 * The original message text will be sent as-is, unless text is being entered
 * The original attachments are sent as they are, unless attachments are being added or removed
diff --git a/app/src/main/java/eu/faircode/email/FragmentMessages.java b/app/src/main/java/eu/faircode/email/FragmentMessages.java
index c8b7ff9393..f77313b723 100644
--- a/app/src/main/java/eu/faircode/email/FragmentMessages.java
+++ b/app/src/main/java/eu/faircode/email/FragmentMessages.java
@@ -238,6 +238,7 @@ import javax.mail.MessageRemovedException;
 import javax.mail.MessagingException;
 import javax.mail.Part;
 import javax.mail.Session;
+import javax.mail.internet.AddressException;
 import javax.mail.internet.InternetAddress;
 import javax.mail.internet.MimeMessage;
 
@@ -2790,6 +2791,15 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                             }
                 }
 
+                boolean canResend = true;
+                for (Address r : recipients) {
+                    String email = ((InternetAddress) r).getAddress();
+                    if ("undisclosed-recipients:".equals(email)) {
+                        canResend = false;
+                        break;
+                    }
+                }
+
                 PopupMenuLifecycle popupMenu = new PopupMenuLifecycle(context, getViewLifecycleOwner(), anchor);
                 popupMenu.inflate(R.menu.popup_reply);
                 popupMenu.getMenu().findItem(R.id.menu_reply_to_all).setVisible(recipients.length > 0);
@@ -2799,6 +2809,7 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                 popupMenu.getMenu().findItem(R.id.menu_reply_hard_bounce).setEnabled(canBounce);
                 popupMenu.getMenu().findItem(R.id.menu_new_message).setVisible(to != null && to.length > 0);
                 popupMenu.getMenu().findItem(R.id.menu_resend).setVisible(experiments);
+                popupMenu.getMenu().findItem(R.id.menu_resend).setEnabled(canResend);
                 popupMenu.getMenu().findItem(R.id.menu_reply_answer).setVisible(answers != 0 || !ActivityBilling.isPro(context));
 
                 popupMenu.getMenu().findItem(R.id.menu_reply_to_sender).setEnabled(message.content);
diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index 49e19b235b..70634b1ff7 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -318,46 +318,49 @@ public class MessageHelper {
             ByteArrayInputStream bis = new ByteArrayInputStream(message.headers.getBytes());
             List<Header> headers = Collections.list(new InternetHeaders(bis).getAllHeaders());
 
-            for (Header header : headers) {
-                String name = header.getName();
-                String value = header.getValue();
-                if (name == null || TextUtils.isEmpty(value))
-                    continue;
+            for (Header header : headers)
+                try {
+                    String name = header.getName();
+                    String value = header.getValue();
+                    if (name == null || TextUtils.isEmpty(value))
+                        continue;
 
-                switch (name.toLowerCase(Locale.ROOT)) {
-                    case "date":
-                        imessage.setHeader("Date", value);
-                        break;
-                    case "from":
-                        imessage.setFrom(value);
-                        break;
-                    case "to":
-                        imessage.setRecipients(Message.RecipientType.TO, InternetAddress.parse(value));
-                        break;
-                    case "cc":
-                        imessage.setRecipients(Message.RecipientType.CC, InternetAddress.parse(value));
-                        break;
-                    case "bcc":
-                        imessage.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(value));
-                        break;
-                    case "reply-to":
-                        imessage.setReplyTo(InternetAddress.parse(value));
-                        break;
-                    case "message-id":
-                        if (send) {
-                            imessage.setHeader("Resent-Message-ID", message.msgid);
-                            imessage.updateMessageID(value);
-                        }
-                        break;
-                    case "references":
-                        imessage.setHeader("References", value);
-                        break;
-                    case "in-reply-to":
-                        imessage.setHeader("In-Reply-To", value);
-                        break;
-                    // Resent-Sender (=on behalf of)
+                    switch (name.toLowerCase(Locale.ROOT)) {
+                        case "date":
+                            imessage.setHeader("Date", value);
+                            break;
+                        case "from":
+                            imessage.setFrom(value);
+                            break;
+                        case "to":
+                            imessage.setRecipients(Message.RecipientType.TO, InternetAddress.parse(value));
+                            break;
+                        case "cc":
+                            imessage.setRecipients(Message.RecipientType.CC, InternetAddress.parse(value));
+                            break;
+                        case "bcc":
+                            imessage.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(value));
+                            break;
+                        case "reply-to":
+                            imessage.setReplyTo(InternetAddress.parse(value));
+                            break;
+                        case "message-id":
+                            if (send) {
+                                imessage.setHeader("Resent-Message-ID", message.msgid);
+                                imessage.updateMessageID(value);
+                            }
+                            break;
+                        case "references":
+                            imessage.setHeader("References", value);
+                            break;
+                        case "in-reply-to":
+                            imessage.setHeader("In-Reply-To", value);
+                            break;
+                        // Resent-Sender (=on behalf of)
+                    }
+                } catch (Throwable ex) {
+                    Log.e(ex);
                 }
-            }
 
             // The "Resent-Date:" indicates the date and time at which the resent
             //   message is dispatched by the resender of the message.