diff --git a/app/src/main/java/eu/faircode/email/AdapterAttachment.java b/app/src/main/java/eu/faircode/email/AdapterAttachment.java
index 737a56ff4b..bc69ae7fd5 100644
--- a/app/src/main/java/eu/faircode/email/AdapterAttachment.java
+++ b/app/src/main/java/eu/faircode/email/AdapterAttachment.java
@@ -216,6 +216,9 @@ public class AdapterAttachment extends RecyclerView.Adapter<AdapterAttachment.Vi
             for (ResolveInfo ri : ris) {
                 if ("com.adobe.reader".equals(ri.activityInfo.packageName))
                     Toast.makeText(context, R.string.title_no_adobe, Toast.LENGTH_LONG).show();
+                if (ri.activityInfo.packageName.startsWith("com.microsoft.office."))
+                    Toast.makeText(context, R.string.title_no_microsoft, Toast.LENGTH_LONG).show();
+
                 Log.i("Target=" + ri);
                 context.grantUriPermission(ri.activityInfo.packageName, uri, Intent.FLAG_GRANT_READ_URI_PERMISSION);
                 targets.add(new NameResolveInfo(
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index da31d99333..cc99ffd996 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -530,7 +530,8 @@
     <string name="title_fix">Fix</string>
     <string name="title_enable">Enable</string>
     <string name="title_no_ask_again">Do not ask this again</string>
-    <string name="title_no_adobe">Adobe Acrobat reader cannot open safely shared files, see the FAQ for more information</string>
+    <string name="title_no_adobe">Adobe Acrobat reader cannot safely open shared files, see the FAQ for more information</string>
+    <string name="title_no_microsoft">Microsoft apps cannot safely open shared files, see the FAQ for more information</string>
     <string name="title_no_body">No message text found</string>
     <string name="title_no_charset">Unsupported encoding: %1$s</string>
     <string name="title_via">Via: %1$s</string>