diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index 4fd579c749..56f3c32dc3 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -135,6 +135,10 @@ class Core {
     private static final int SYNC_CHUNCK_SIZE = 200;
     private static final int SYNC_BATCH_SIZE = 20;
     private static final int DOWNLOAD_BATCH_SIZE = 20;
+    private static final int SYNC_YIELD_COUNT = 100;
+    private static final long SYNC_YIELD_DURATION = 1000; // milliseconds
+    private static final int DOWNLOAD_YIELD_COUNT = 25;
+    private static final long DOWNLOAD_YIELD_DURATION = 1000; // milliseconds
     private static final long YIELD_DURATION = 200L; // milliseconds
     private static final long JOIN_WAIT = 180 * 1000L; // milliseconds
     private static final long FUTURE_RECEIVED = 30 * 24 * 3600 * 1000L; // milliseconds
@@ -2344,6 +2348,7 @@ class Core {
                 fp.add(GmailFolder.FetchProfileItem.THRID);
 
             // Add/update local messages
+            int synced = 0;
             Long[] ids = new Long[imessages.length];
             Log.i(folder.name + " add=" + imessages.length);
             for (int i = imessages.length - 1; i >= 0 && state.isRunning() && state.isRecoverable(); i -= SYNC_BATCH_SIZE) {
@@ -2399,6 +2404,15 @@ class Core {
                                 false, download && initialize == 0,
                                 rules, state, stats);
                         ids[from + j] = (message == null || message.ui_hide ? null : message.id);
+
+                        if (message != null && full.contains(isub[j]))
+                            if ((++synced % SYNC_YIELD_COUNT) == 0)
+                                try {
+                                    Log.i(folder.name + " yield synced=" + synced);
+                                    Thread.sleep(SYNC_YIELD_DURATION);
+                                } catch (InterruptedException ex) {
+                                    Log.w(ex);
+                                }
                     } catch (MessageRemovedException ex) {
                         Log.w(folder.name, ex);
                     } catch (FolderClosedException ex) {
@@ -2442,6 +2456,7 @@ class Core {
                 db.folder().setFolderSyncState(folder.id, "downloading");
 
                 // Download messages/attachments
+                int downloaded = 0;
                 Log.i(folder.name + " download=" + imessages.length);
                 for (int i = imessages.length - 1; i >= 0 && state.isRunning() && state.isRecoverable(); i -= DOWNLOAD_BATCH_SIZE) {
                     int from = Math.max(0, i - DOWNLOAD_BATCH_SIZE + 1);
@@ -2461,12 +2476,19 @@ class Core {
                     for (int j = isub.length - 1; j >= 0 && state.isRunning() && state.isRecoverable(); j--)
                         try {
                             if (ids[from + j] != null)
-                                downloadMessage(
+                                if (downloadMessage(
                                         context,
                                         account, folder,
                                         istore, ifolder,
                                         (MimeMessage) isub[j], ids[from + j],
-                                        state, stats);
+                                        state, stats))
+                                    if ((++downloaded % DOWNLOAD_YIELD_COUNT) == 0)
+                                        try {
+                                            Log.i(folder.name + " yield downloaded=" + downloaded);
+                                            Thread.sleep(DOWNLOAD_YIELD_DURATION);
+                                        } catch (InterruptedException ex) {
+                                            Log.w(ex);
+                                        }
                         } catch (FolderClosedException ex) {
                             throw ex;
                         } catch (Throwable ex) {
@@ -3163,18 +3185,18 @@ class Core {
         }
     }
 
-    private static void downloadMessage(
+    private static boolean downloadMessage(
             Context context,
             EntityAccount account, EntityFolder folder,
             IMAPStore istore, IMAPFolder ifolder,
             MimeMessage imessage, long id, State state, SyncStats stats) throws MessagingException, IOException {
         if (state.getNetworkState().isRoaming())
-            return;
+            return false;
 
         DB db = DB.getInstance(context);
         EntityMessage message = db.message().getMessage(id);
         if (message == null || message.ui_hide)
-            return;
+            return false;
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         long maxSize = prefs.getInt("download", MessageHelper.DEFAULT_DOWNLOAD_SIZE);
@@ -3254,6 +3276,8 @@ class Core {
                             db.attachment().setError(attachment.id, Log.formatThrowable(ex, false));
                         }
         }
+
+        return fetch;
     }
 
     private static void reportEmptyMessage(Context context, State state, EntityAccount account, IMAPStore istore) {