diff --git a/k9mail/src/main/java/com/fsck/k9/activity/MessageLoaderHelper.java b/k9mail/src/main/java/com/fsck/k9/activity/MessageLoaderHelper.java
index 54787eb63..954cf6208 100644
--- a/k9mail/src/main/java/com/fsck/k9/activity/MessageLoaderHelper.java
+++ b/k9mail/src/main/java/com/fsck/k9/activity/MessageLoaderHelper.java
@@ -81,6 +81,7 @@ public class MessageLoaderHelper {
     private LoaderManager loaderManager;
     @Nullable // make this explicitly nullable, make sure to cancel/ignore any operation if this is null
     private MessageLoaderCallbacks callback;
+    private final boolean processSignedOnly;
 
 
     // transient state
@@ -100,6 +101,8 @@ public class MessageLoaderHelper {
         this.loaderManager = loaderManager;
         this.fragmentManager = fragmentManager;
         this.callback = callback;
+
+        processSignedOnly = K9.getOpenPgpSupportSignOnly();
     }
 
 
@@ -276,7 +279,7 @@ public class MessageLoaderHelper {
             retainCryptoHelperFragment.setData(messageCryptoHelper);
         }
         messageCryptoHelper.asyncStartOrResumeProcessingMessage(
-                localMessage, messageCryptoCallback, cachedDecryptionResult);
+                localMessage, messageCryptoCallback, cachedDecryptionResult, processSignedOnly);
     }
 
     private void cancelAndClearCryptoOperation() {
diff --git a/k9mail/src/main/java/com/fsck/k9/ui/crypto/MessageCryptoHelper.java b/k9mail/src/main/java/com/fsck/k9/ui/crypto/MessageCryptoHelper.java
index b8e7e2e86..94eacf467 100644
--- a/k9mail/src/main/java/com/fsck/k9/ui/crypto/MessageCryptoHelper.java
+++ b/k9mail/src/main/java/com/fsck/k9/ui/crypto/MessageCryptoHelper.java
@@ -84,6 +84,7 @@ public class MessageCryptoHelper {
     private State state;
     private CancelableBackgroundOperation cancelableBackgroundOperation;
     private boolean isCancelled;
+    private boolean processSignedOnly;
 
     private OpenPgpApi openPgpApi;
     private OpenPgpServiceConnection openPgpServiceConnection;
@@ -108,7 +109,7 @@ public class MessageCryptoHelper {
     }
 
     public void asyncStartOrResumeProcessingMessage(Message message, MessageCryptoCallback callback,
-            OpenPgpDecryptionResult cachedDecryptionResult) {
+            OpenPgpDecryptionResult cachedDecryptionResult, boolean processSignedOnly) {
         if (this.currentMessage != null) {
             reattachCallback(message, callback);
             return;
@@ -119,6 +120,7 @@ public class MessageCryptoHelper {
         this.currentMessage = message;
         this.cachedDecryptionResult = cachedDecryptionResult;
         this.callback = callback;
+        this.processSignedOnly = processSignedOnly;
 
         nextStep();
     }
@@ -143,6 +145,13 @@ public class MessageCryptoHelper {
         List<Part> signedParts = MessageCryptoStructureDetector
                 .findMultipartSignedParts(currentMessage, messageAnnotations);
         for (Part part : signedParts) {
+            if (!processSignedOnly) {
+                boolean isEncapsulatedSignature =
+                        messageAnnotations.findKeyForAnnotationWithReplacementPart(part) != null;
+                if (!isEncapsulatedSignature) {
+                    continue;
+                }
+            }
             if (!MessageHelper.isCompletePartAvailable(part)) {
                 MimeBodyPart replacementPart = getMultipartSignedContentPartIfAvailable(part);
                 addErrorAnnotation(part, CryptoError.OPENPGP_SIGNED_BUT_INCOMPLETE, replacementPart);
@@ -161,12 +170,15 @@ public class MessageCryptoHelper {
     private void findPartsForPgpInlinePass() {
         List<Part> inlineParts = MessageCryptoStructureDetector.findPgpInlineParts(currentMessage);
         for (Part part : inlineParts) {
+            if (!processSignedOnly && !MessageCryptoStructureDetector.isPartPgpInlineEncrypted(part)) {
+                continue;
+            }
+
             if (!currentMessage.getFlags().contains(Flag.X_DOWNLOADED_FULL)) {
                 if (MessageCryptoStructureDetector.isPartPgpInlineEncrypted(part)) {
                     addErrorAnnotation(part, CryptoError.OPENPGP_ENCRYPTED_BUT_INCOMPLETE, NO_REPLACEMENT_PART);
                 } else {
-                    MimeBodyPart replacementPart = extractClearsignedTextReplacementPart(part);
-                    addErrorAnnotation(part, CryptoError.OPENPGP_SIGNED_BUT_INCOMPLETE, replacementPart);
+                    addErrorAnnotation(part, CryptoError.OPENPGP_SIGNED_BUT_INCOMPLETE, NO_REPLACEMENT_PART);
                 }
                 continue;
             }
diff --git a/k9mail/src/test/java/com/fsck/k9/ui/crypto/MessageCryptoHelperTest.java b/k9mail/src/test/java/com/fsck/k9/ui/crypto/MessageCryptoHelperTest.java
index d35f529d0..02ea5f485 100644
--- a/k9mail/src/test/java/com/fsck/k9/ui/crypto/MessageCryptoHelperTest.java
+++ b/k9mail/src/test/java/com/fsck/k9/ui/crypto/MessageCryptoHelperTest.java
@@ -84,7 +84,7 @@ public class MessageCryptoHelperTest {
         message.setHeader("Content-Type", "text/plain");
 
         MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
 
         ArgumentCaptor<MessageCryptoAnnotations> captor = ArgumentCaptor.forClass(MessageCryptoAnnotations.class);
         verify(messageCryptoCallback).onCryptoOperationsFinished(captor.capture());
@@ -107,7 +107,7 @@ public class MessageCryptoHelperTest {
 
 
         MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
 
 
         ArgumentCaptor<MessageCryptoAnnotations> captor = ArgumentCaptor.forClass(MessageCryptoAnnotations.class);
@@ -132,7 +132,7 @@ public class MessageCryptoHelperTest {
         );
 
         MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, true);
 
         assertPartAnnotationHasState(message, messageCryptoCallback, CryptoError.OPENPGP_SIGNED_BUT_INCOMPLETE, null,
                 null, null, null);
@@ -148,7 +148,7 @@ public class MessageCryptoHelperTest {
         );
 
         MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
 
         assertPartAnnotationHasState(
                 message, messageCryptoCallback, CryptoError.OPENPGP_ENCRYPTED_BUT_INCOMPLETE, null, null, null, null);
@@ -164,7 +164,7 @@ public class MessageCryptoHelperTest {
         );
 
         MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
 
         assertPartAnnotationHasState(message, messageCryptoCallback, CryptoError.ENCRYPTED_BUT_UNSUPPORTED, null, null,
                 null, null);
@@ -180,7 +180,7 @@ public class MessageCryptoHelperTest {
         );
 
         MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, true);
 
         assertPartAnnotationHasState(message, messageCryptoCallback, CryptoError.SIGNED_BUT_UNSUPPORTED, null, null,
                 null, null);
@@ -210,6 +210,36 @@ public class MessageCryptoHelperTest {
         verifyNoMoreInteractions(autocryptOperations);
     }
 
+    @Test
+    public void multipartSigned__withSignOnlyDisabled__shouldReturnNothing() throws Exception {
+        Message message = messageFromBody(
+                multipart("signed", "application/pgp-signature",
+                        bodypart("text/plain", "content"),
+                        bodypart("application/pgp-signature", "content")
+                )
+        );
+
+        MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
+
+        assertReturnsWithNoCryptoAnnotations(messageCryptoCallback);
+    }
+
+    @Test
+    public void multipartSigned__withSignOnlyDisabledAndNullBody__shouldReturnNothing() throws Exception {
+        Message message = messageFromBody(
+                multipart("signed", "application/pgp-signature",
+                        bodypart("text/plain"),
+                        bodypart("application/pgp-signature")
+                )
+        );
+
+        MessageCryptoCallback messageCryptoCallback = mock(MessageCryptoCallback.class);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
+
+        assertReturnsWithNoCryptoAnnotations(messageCryptoCallback);
+    }
+
     @Test
     public void multipartEncrypted__shouldCallOpenPgpApiAsync() throws Exception {
         Body encryptedBody;
@@ -249,7 +279,7 @@ public class MessageCryptoHelperTest {
 
     private void processEncryptedMessageAndCaptureMocks(Message message, Body encryptedBody, OutputStream outputStream)
             throws Exception {
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, false);
 
         ArgumentCaptor<Intent> intentCaptor = ArgumentCaptor.forClass(Intent.class);
         ArgumentCaptor<OpenPgpDataSource> dataSourceCaptor = ArgumentCaptor.forClass(OpenPgpDataSource.class);
@@ -267,7 +297,7 @@ public class MessageCryptoHelperTest {
 
     private void processSignedMessageAndCaptureMocks(Message message, BodyPart signedBodyPart,
             OutputStream outputStream) throws Exception {
-        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null);
+        messageCryptoHelper.asyncStartOrResumeProcessingMessage(message, messageCryptoCallback, null, true);
 
         ArgumentCaptor<Intent> intentCaptor = ArgumentCaptor.forClass(Intent.class);
         ArgumentCaptor<OpenPgpDataSource> dataSourceCaptor = ArgumentCaptor.forClass(OpenPgpDataSource.class);
@@ -283,6 +313,15 @@ public class MessageCryptoHelperTest {
         verify(signedBodyPart).writeTo(outputStream);
     }
 
+    private void assertReturnsWithNoCryptoAnnotations(MessageCryptoCallback messageCryptoCallback) {
+        ArgumentCaptor<MessageCryptoAnnotations> captor = ArgumentCaptor.forClass(MessageCryptoAnnotations.class);
+        verify(messageCryptoCallback).onCryptoOperationsFinished(captor.capture());
+        verifyNoMoreInteractions(messageCryptoCallback);
+
+        MessageCryptoAnnotations annotations = captor.getValue();
+        assertTrue(annotations.isEmpty());
+    }
+
     private void assertPartAnnotationHasState(Message message, MessageCryptoCallback messageCryptoCallback,
             CryptoError cryptoErrorState, MimeBodyPart replacementPart, OpenPgpDecryptionResult openPgpDecryptionResult,
             OpenPgpSignatureResult openPgpSignatureResult, PendingIntent openPgpPendingIntent) {