diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index 62dff428dc..ad6c404d6a 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -964,9 +964,11 @@ class Core {
             boolean sync_unseen = prefs.getBoolean("sync_unseen", false);
             boolean sync_flagged = prefs.getBoolean("sync_flagged", true);
             boolean sync_kept = prefs.getBoolean("sync_kept", true);
+            boolean delete_unseen = prefs.getBoolean("delete_unseen", false);
 
             Log.i(folder.name + " start sync after=" + sync_days + "/" + keep_days +
-                    " sync unseen=" + sync_unseen + " flagged=" + sync_flagged + " kept=" + sync_kept);
+                    " sync unseen=" + sync_unseen + " flagged=" + sync_flagged +
+                    " delete unseen=" + delete_unseen + " kept=" + sync_kept);
 
             db.folder().setFolderSyncState(folder.id, "syncing");
 
@@ -997,7 +999,7 @@ class Core {
 
             // Delete old local messages
             if (auto_delete && EntityFolder.TRASH.equals(folder.type)) {
-                List<Long> tbds = db.message().getMessagesBefore(folder.id, keep_time, false);
+                List<Long> tbds = db.message().getMessagesBefore(folder.id, keep_time, delete_unseen);
                 Log.i(folder.name + " local tbd=" + tbds.size());
                 for (Long tbd : tbds) {
                     EntityMessage message = db.message().getMessage(tbd);
@@ -1005,7 +1007,7 @@ class Core {
                         EntityOperation.queue(context, message, EntityOperation.DELETE);
                 }
             } else {
-                int old = db.message().deleteMessagesBefore(folder.id, keep_time, false);
+                int old = db.message().deleteMessagesBefore(folder.id, keep_time, delete_unseen);
                 Log.i(folder.name + " local old=" + old);
             }
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java b/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java
index 39c4fb9668..7c5d4ed860 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java
@@ -55,11 +55,13 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
     private TextView tvSchedulePro;
     private SwitchCompat swUnseen;
     private SwitchCompat swFlagged;
+    private SwitchCompat swDeleteUnseen;
     private SwitchCompat swSyncKept;
     private SwitchCompat swSyncFolders;
 
     private final static String[] RESET_OPTIONS = new String[]{
-            "enabled", "poll_interval", "schedule", "schedule_start", "schedule_end", "sync_unseen", "sync_flagged", "sync_kept", "sync_folders"
+            "enabled", "poll_interval", "schedule", "schedule_start", "schedule_end",
+            "sync_unseen", "sync_flagged", "delete_unseen", "sync_kept", "sync_folders"
     };
 
     @Override
@@ -80,6 +82,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
         tvSchedulePro = view.findViewById(R.id.tvSchedulePro);
         swUnseen = view.findViewById(R.id.swUnseen);
         swFlagged = view.findViewById(R.id.swFlagged);
+        swDeleteUnseen = view.findViewById(R.id.swDeleteUnseen);
         swSyncKept = view.findViewById(R.id.swSyncKept);
         swSyncFolders = view.findViewById(R.id.swSyncFolders);
 
@@ -172,6 +175,14 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
             }
         });
 
+        swDeleteUnseen.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("delete_unseen", checked).apply();
+                ServiceSynchronize.reload(getContext(), false, "delete_unseen=" + checked);
+            }
+        });
+
         swSyncKept.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -251,6 +262,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
 
         swUnseen.setChecked(prefs.getBoolean("sync_unseen", false));
         swFlagged.setChecked(prefs.getBoolean("sync_flagged", true));
+        swDeleteUnseen.setChecked(prefs.getBoolean("delete_unseen", false));
         swSyncKept.setChecked(prefs.getBoolean("sync_kept", true));
         swSyncFolders.setChecked(prefs.getBoolean("sync_folders", true));
     }
diff --git a/app/src/main/res/layout/fragment_options_synchronize.xml b/app/src/main/res/layout/fragment_options_synchronize.xml
index f8367b6e1c..33839aff90 100644
--- a/app/src/main/res/layout/fragment_options_synchronize.xml
+++ b/app/src/main/res/layout/fragment_options_synchronize.xml
@@ -175,6 +175,17 @@
                 app:layout_constraintTop_toBottomOf="@id/swUnseen"
                 app:switchPadding="12dp" />
 
+            <androidx.appcompat.widget.SwitchCompat
+                android:id="@+id/swDeleteUnseen"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:checked="false"
+                android:text="@string/title_advanced_delete_unseen"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/swFlagged"
+                app:switchPadding="12dp" />
+
             <androidx.appcompat.widget.SwitchCompat
                 android:id="@+id/swSyncKept"
                 android:layout_width="match_parent"
@@ -183,7 +194,7 @@
                 android:checked="false"
                 android:text="@string/title_advanced_kept_removed"
                 app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/swFlagged"
+                app:layout_constraintTop_toBottomOf="@id/swDeleteUnseen"
                 app:switchPadding="12dp" />
 
             <TextView
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index c34eeebe2f..7edbb604a5 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -170,6 +170,7 @@
     <string name="title_advanced_schedule">Schedule</string>
     <string name="title_advanced_unseen">All unread messages</string>
     <string name="title_advanced_flagged">All starred messages</string>
+    <string name="title_advanced_delete_unseen">Delete old unread messages</string>
     <string name="title_advanced_kept_removed">Check if old messages were removed from the server</string>
     <string name="title_advanced_sync_folders">Synchronize folder list</string>