diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index 71e7494624..1102bbd32d 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -1923,7 +1923,7 @@ class Core {
                 Log.w(folder.name + " " + ex.getMessage());
 
                 Log.i(folder.name + " fetching raw message uid=" + uid);
-                File file = File.createTempFile("serverbug", "." + uid, context.getCacheDir());
+                File file = File.createTempFile("serverbug." + folder.id, "." + uid, context.getCacheDir());
                 try (OutputStream os = new BufferedOutputStream(new FileOutputStream(file))) {
                     imessage.writeTo(os);
                 }
@@ -1933,7 +1933,7 @@ class Core {
 
                 Log.i(folder.name + " decoding again uid=" + uid);
                 try (InputStream is = new BufferedInputStream(new FileInputStream(file))) {
-                    imessage = new MimeMessage(isession, is);
+                    imessage = new MimeMessageEx(isession, is, imessage);
                 }
 
                 file.delete();
diff --git a/app/src/main/java/eu/faircode/email/MimeMessageEx.java b/app/src/main/java/eu/faircode/email/MimeMessageEx.java
index 8b8abb3eea..046567b8ba 100644
--- a/app/src/main/java/eu/faircode/email/MimeMessageEx.java
+++ b/app/src/main/java/eu/faircode/email/MimeMessageEx.java
@@ -19,18 +19,27 @@ package eu.faircode.email;
     Copyright 2018-2019 by Marcel Bokhorst (M66B)
 */
 
+import java.io.InputStream;
+
+import javax.mail.Flags;
 import javax.mail.MessagingException;
 import javax.mail.Session;
 import javax.mail.internet.MimeMessage;
 
 public class MimeMessageEx extends MimeMessage {
     private String msgid;
+    private MimeMessage original;
 
     MimeMessageEx(Session session, String msgid) {
         super(session);
         this.msgid = msgid;
     }
 
+    MimeMessageEx(Session session, InputStream is, MimeMessage original) throws MessagingException {
+        super(session, is);
+        this.original = original;
+    }
+
     @Override
     public String getMessageID() throws MessagingException {
         if (this.msgid == null)
@@ -48,4 +57,12 @@ public class MimeMessageEx extends MimeMessage {
             Log.i("Override Message-ID=" + msgid);
         }
     }
+
+    @Override
+    public synchronized boolean isSet(Flags.Flag flag) throws MessagingException {
+        if (original == null)
+            return super.isSet(flag);
+        else
+            return original.isSet(flag);
+    }
 }