diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptActivity.java
index 5eb9963f5..4b80af437 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptActivity.java
@@ -162,6 +162,10 @@ public class DecryptActivity extends BaseActivity {
                     Uri uri = intent.getData();
                     if (uri != null) {
 
+                        if ("com.fsck.k9.attachmentprovider".equals(uri.getHost())) {
+                            Toast.makeText(this, R.string.error_reading_k9, Toast.LENGTH_LONG).show();
+                        }
+
                         if ("com.android.email.attachmentprovider".equals(uri.getHost())) {
                             Toast.makeText(this, R.string.error_reading_aosp, Toast.LENGTH_LONG).show();
                             finish();
diff --git a/OpenKeychain/src/main/res/values/strings.xml b/OpenKeychain/src/main/res/values/strings.xml
index d0939026c..0db982a8b 100644
--- a/OpenKeychain/src/main/res/values/strings.xml
+++ b/OpenKeychain/src/main/res/values/strings.xml
@@ -1540,7 +1540,8 @@
     <string name="error_loading_keys">"Error loading keys!"</string>
     <string name="error_empty_log">"(error, empty log)"</string>
     <string name="error_reading_text">"Could not read input to decrypt!"</string>
-    <string name="error_reading_aosp">"Failed reading data, this is a bug in the Android E-Mail client!"</string>
+    <string name="error_reading_aosp">"Failed reading data, this is a bug in the Android E-Mail client! (Issue #290)"</string>
+    <string name="error_reading_k9">"If decryption fails, press 'Download complete message' in K-9 Mail!"</string>
     <string name="filename_unknown">Unknown filename (click to open)</string>
     <string name="filename_unknown_text">Text (click to show)</string>
     <string name="intent_show">Show Signed/Encrypted Content</string>