diff --git a/app/src/main/java/eu/faircode/email/ActivityMain.java b/app/src/main/java/eu/faircode/email/ActivityMain.java
index 3fa144f317..def1fd1650 100644
--- a/app/src/main/java/eu/faircode/email/ActivityMain.java
+++ b/app/src/main/java/eu/faircode/email/ActivityMain.java
@@ -51,7 +51,7 @@ public class ActivityMain extends ActivityBase implements FragmentManager.OnBack
     private static final long IGNORE_STORAGE_SPACE = 24 * 60 * 60 * 1000L; // milliseconds
 
     private static final ExecutorService executor =
-            Helper.getBackgroundExecutor(0, 1, 3, "main");
+            Helper.getBackgroundExecutor(1, "main");
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index f8a6945290..dede7b83c8 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -337,9 +337,9 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
     private DateFormat DTF;
 
     private static final ExecutorService executorDiffer =
-            Helper.getBackgroundExecutor(0, 0, 3, "differ");
+            Helper.getBackgroundExecutor(0, "differ");
     private static final ExecutorService executorAvatar =
-            Helper.getBackgroundExecutor(0, 0, 3, "avatar");
+            Helper.getBackgroundExecutor(0, "avatar");
 
     private static final int MAX_RECIPIENTS_COMPACT = 3;
     private static final int MAX_RECIPIENTS_NORMAL = 7;
diff --git a/app/src/main/java/eu/faircode/email/DB.java b/app/src/main/java/eu/faircode/email/DB.java
index 0c43541656..da80770621 100644
--- a/app/src/main/java/eu/faircode/email/DB.java
+++ b/app/src/main/java/eu/faircode/email/DB.java
@@ -127,7 +127,7 @@ public abstract class DB extends RoomDatabase {
     private static final int DB_CHECKPOINT = 1000; // requery/sqlite-android default
 
     private static ExecutorService executor =
-            Helper.getBackgroundExecutor(1, 0, 3, "db");
+            Helper.getBackgroundExecutor(0, "db");
 
     private static final String[] DB_TABLES = new String[]{
             "identity", "account", "folder", "message", "attachment", "operation", "contact", "certificate", "answer", "rule", "search", "log"};
diff --git a/app/src/main/java/eu/faircode/email/Helper.java b/app/src/main/java/eu/faircode/email/Helper.java
index 5915ec3a9f..d3f5bad91a 100644
--- a/app/src/main/java/eu/faircode/email/Helper.java
+++ b/app/src/main/java/eu/faircode/email/Helper.java
@@ -268,19 +268,19 @@ public class Helper {
 
     static ExecutorService getUIExecutor() {
         if (sUIExecutor == null)
-            sUIExecutor = getBackgroundExecutor(0, 0, 3, "UI");
+            sUIExecutor = getBackgroundExecutor(0, "UI");
         return sUIExecutor;
     }
 
     static ExecutorService getMediaTaskExecutor() {
         if (sMediaExecutor == null)
-            sMediaExecutor = getBackgroundExecutor(0, 1, 3, "media");
+            sMediaExecutor = getBackgroundExecutor(1, "media");
         return sMediaExecutor;
     }
 
     static ExecutorService getDownloadTaskExecutor() {
         if (sDownloadExecutor == null)
-            sDownloadExecutor = getBackgroundExecutor(0, 0, 3, "download");
+            sDownloadExecutor = getBackgroundExecutor(0, "download");
         return sDownloadExecutor;
     }
 
@@ -295,10 +295,6 @@ public class Helper {
     }
 
     static ExecutorService getBackgroundExecutor(int threads, final String name) {
-        return getBackgroundExecutor(threads == 0 ? -1 : threads, threads, 3, name);
-    }
-
-    static ExecutorService getBackgroundExecutor(int min, int max, int keepalive, final String name) {
         ThreadFactory factory = new ThreadFactory() {
             private final AtomicInteger threadId = new AtomicInteger();
 
@@ -324,22 +320,23 @@ public class Helper {
             }
         };
 
-        if (max == 0) {
+        if (threads == 0) {
             // java.lang.OutOfMemoryError: pthread_create (1040KB stack) failed: Try again
             // 1040 KB native stack size / 32 KB thread stack size ~ 32 threads
             int processors = Runtime.getRuntime().availableProcessors(); // Modern devices: 8
+            threads = Math.max(8, processors * 2) + 1;
             return new ThreadPoolExecutorEx(
                     name,
-                    min < 0 ? Math.max(2, processors / 2 + 1) : min,
-                    Math.max(8, processors * 2) + 1,
-                    keepalive, TimeUnit.SECONDS,
+                    threads,
+                    threads,
+                    3, TimeUnit.SECONDS,
                     new LinkedBlockingQueue<Runnable>(),
                     factory);
-        } else if (max == 1)
+        } else if (threads == 1)
             return new ThreadPoolExecutorEx(
                     name,
-                    min, max,
-                    keepalive, TimeUnit.SECONDS,
+                    threads, threads,
+                    3, TimeUnit.SECONDS,
                     new PriorityBlockingQueue<Runnable>(10, new PriorityComparator()),
                     factory) {
                 private final AtomicLong sequenceId = new AtomicLong();
@@ -358,8 +355,8 @@ public class Helper {
         else
             return new ThreadPoolExecutorEx(
                     name,
-                    min, max,
-                    keepalive, TimeUnit.SECONDS,
+                    threads, threads,
+                    3, TimeUnit.SECONDS,
                     new LinkedBlockingQueue<Runnable>(),
                     factory);
     }
@@ -374,6 +371,8 @@ public class Helper {
                 BlockingQueue<Runnable> workQueue,
                 ThreadFactory threadFactory) {
             super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory);
+            if (keepAliveTime != 0)
+                allowCoreThreadTimeOut(true);
             this.name = name;
         }
 
diff --git a/app/src/main/java/eu/faircode/email/ServiceSend.java b/app/src/main/java/eu/faircode/email/ServiceSend.java
index 661c81246c..3551ec7d84 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSend.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSend.java
@@ -85,7 +85,7 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
     private List<Long> handling = new ArrayList<>();
 
     private static final ExecutorService executor =
-            Helper.getBackgroundExecutor(0, 1, 3, "send");
+            Helper.getBackgroundExecutor(1, "send");
 
     private static final int RETRY_MAX = 3;
     private static final int CONNECTIVITY_DELAY = 5000; // milliseconds
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index e415123a56..87da82da4a 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -129,9 +129,9 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
     private final MediatorState liveAccountNetworkState = new MediatorState();
 
     private static final ExecutorService executorService =
-            Helper.getBackgroundExecutor(1, 1, 0, "sync");
+            Helper.getBackgroundExecutor(1, "sync");
     private static final ExecutorService executorNotify =
-            Helper.getBackgroundExecutor(0, 1, 3, "notify");
+            Helper.getBackgroundExecutor(1, "notify");
 
     private static final long BACKUP_DELAY = 30 * 1000L; // milliseconds
     private static final long PURGE_DELAY = 30 * 1000L; // milliseconds
diff --git a/app/src/main/java/eu/faircode/email/SimpleTask.java b/app/src/main/java/eu/faircode/email/SimpleTask.java
index 4098c34585..cded64d90c 100644
--- a/app/src/main/java/eu/faircode/email/SimpleTask.java
+++ b/app/src/main/java/eu/faircode/email/SimpleTask.java
@@ -45,7 +45,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
-import java.util.concurrent.RunnableFuture;
 import java.util.concurrent.ThreadPoolExecutor;
 
 // This simple task is simple to use, but it is also simple to cause bugs that can easily lead to crashes
@@ -74,10 +73,10 @@ public abstract class SimpleTask<T> implements LifecycleObserver {
     private static final List<SimpleTask> tasks = new ArrayList<>();
 
     private static final ExecutorService serialExecutor =
-            Helper.getBackgroundExecutor(0, 1, 3, "tasks/serial");
+            Helper.getBackgroundExecutor(1, "tasks/serial");
 
     private static final ExecutorService globalExecutor =
-            Helper.getBackgroundExecutor(0, 0, 3, "tasks/global");
+            Helper.getBackgroundExecutor(0, "tasks/global");
 
     private static final int REPORT_AFTER = 15 * 60 * 1000; // milliseconds
 
diff --git a/app/src/main/java/eu/faircode/email/TextHelper.java b/app/src/main/java/eu/faircode/email/TextHelper.java
index 1ea5e39e56..ed35a62b2b 100644
--- a/app/src/main/java/eu/faircode/email/TextHelper.java
+++ b/app/src/main/java/eu/faircode/email/TextHelper.java
@@ -68,7 +68,7 @@ public class TextHelper {
     private static final long MAX_CONVERSATION_DURATION = 3000; // milliseconds
 
     private static final ExecutorService executor =
-            Helper.getBackgroundExecutor(0, 1, 3, "text");
+            Helper.getBackgroundExecutor(1, "text");
 
     static {
         System.loadLibrary("fairemail");
diff --git a/app/src/main/java/eu/faircode/email/ViewModelMessages.java b/app/src/main/java/eu/faircode/email/ViewModelMessages.java
index 3e26791ed9..567504e16f 100644
--- a/app/src/main/java/eu/faircode/email/ViewModelMessages.java
+++ b/app/src/main/java/eu/faircode/email/ViewModelMessages.java
@@ -69,7 +69,7 @@ public class ViewModelMessages extends ViewModel {
     };
 
     private static final ExecutorService executor =
-            Helper.getBackgroundExecutor(0, 0, 3, "model");
+            Helper.getBackgroundExecutor(0, "model");
 
     private static final int LOCAL_PAGE_SIZE = 50;
     private static final int THREAD_PAGE_SIZE = 100;