diff --git a/app/src/main/java/eu/faircode/email/AdapterAttachment.java b/app/src/main/java/eu/faircode/email/AdapterAttachment.java
index 5835d7b840..907d999f6a 100644
--- a/app/src/main/java/eu/faircode/email/AdapterAttachment.java
+++ b/app/src/main/java/eu/faircode/email/AdapterAttachment.java
@@ -227,7 +227,7 @@ public class AdapterAttachment extends RecyclerView.Adapter<AdapterAttachment.Vi
 
             // Build intent
             Intent intent = new Intent(Intent.ACTION_VIEW);
-            intent.setDataAndType(uri, type);
+            intent.setDataAndTypeAndNormalize(uri, type);
             intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
             if (!TextUtils.isEmpty(attachment.name))
                 intent.putExtra(Intent.EXTRA_TITLE, Helper.sanitizeFilename(attachment.name));
diff --git a/app/src/main/java/eu/faircode/email/AdapterImage.java b/app/src/main/java/eu/faircode/email/AdapterImage.java
index 21c2cc922b..d0048bf227 100644
--- a/app/src/main/java/eu/faircode/email/AdapterImage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterImage.java
@@ -115,7 +115,7 @@ public class AdapterImage extends RecyclerView.Adapter<AdapterImage.ViewHolder>
 
                 // Build intent
                 Intent intent = new Intent(Intent.ACTION_VIEW);
-                intent.setDataAndType(uri, attachment.type);
+                intent.setDataAndTypeAndNormalize(uri, attachment.type);
                 intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
                 if (!TextUtils.isEmpty(attachment.name))
                     intent.putExtra(Intent.EXTRA_TITLE, attachment.name);
diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 87c9794889..1d73a2dc0b 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -2417,7 +2417,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                         Uri lookupUri = ContactsContract.Contacts.getLookupUri(contactId, lookupKey);
 
                         edit.setAction(Intent.ACTION_EDIT);
-                        edit.setDataAndType(lookupUri, ContactsContract.Contacts.CONTENT_ITEM_TYPE);
+                        edit.setDataAndTypeAndNormalize(lookupUri, ContactsContract.Contacts.CONTENT_ITEM_TYPE);
                     } else {
                         edit.setAction(Intent.ACTION_INSERT);
                         edit.setType(ContactsContract.Contacts.CONTENT_TYPE);
diff --git a/app/src/main/java/eu/faircode/email/EntityAttachment.java b/app/src/main/java/eu/faircode/email/EntityAttachment.java
index 87a0522c8d..4070084897 100644
--- a/app/src/main/java/eu/faircode/email/EntityAttachment.java
+++ b/app/src/main/java/eu/faircode/email/EntityAttachment.java
@@ -154,6 +154,8 @@ public class EntityAttachment {
         if (encryption != null)
             return type;
 
+        // https://blogs.msdn.microsoft.com/vsofficedeveloper/2008/05/08/office-2007-file-format-mime-types-for-http-content-streaming-2/
+
         String extension = Helper.getExtension(name);
         if (extension == null)
             return type;