diff --git a/src/main/java/org/jabref/JabRefException.java b/src/main/java/org/jabref/JabRefException.java
index ba3e85a539a..42eacc77c72 100644
--- a/src/main/java/org/jabref/JabRefException.java
+++ b/src/main/java/org/jabref/JabRefException.java
@@ -5,9 +5,8 @@
 
 public class JabRefException extends Exception {
 
-    private String localizedMessage;
-
     private static final Log LOGGER = LogFactory.getLog(JabRefException.class);
+    private String localizedMessage;
 
     public JabRefException(String message) {
         super(message);
@@ -34,7 +33,7 @@ public JabRefException(Throwable cause) {
     @Override
     public String getLocalizedMessage() {
         if (localizedMessage == null) {
-            LOGGER.warn("No localized message exception message defined. Falling back to getMessage().");
+            LOGGER.debug("No localized message exception message defined. Falling back to getMessage().");
             return getMessage();
         } else {
             return localizedMessage;
diff --git a/src/main/java/org/jabref/gui/logging/GuiAppender.java b/src/main/java/org/jabref/gui/logging/GuiAppender.java
index 14e71ac3a80..d6a6f25ebd6 100644
--- a/src/main/java/org/jabref/gui/logging/GuiAppender.java
+++ b/src/main/java/org/jabref/gui/logging/GuiAppender.java
@@ -2,6 +2,7 @@
 
 import java.io.Serializable;
 
+import org.jabref.gui.util.DefaultTaskExecutor;
 import org.jabref.logic.logging.LogMessages;
 
 import org.apache.logging.log4j.core.Filter;
@@ -43,6 +44,6 @@ public static GuiAppender createAppender(@PluginAttribute("name") String name,
      */
     @Override
     public void append(LogEvent event) {
-        LogMessages.getInstance().add(event);
+        DefaultTaskExecutor.runInJavaFXThread(() -> LogMessages.getInstance().add(event));
     }
 }
diff --git a/src/main/java/org/jabref/gui/util/DefaultTaskExecutor.java b/src/main/java/org/jabref/gui/util/DefaultTaskExecutor.java
index 826ba4aa779..63b0a615cb0 100644
--- a/src/main/java/org/jabref/gui/util/DefaultTaskExecutor.java
+++ b/src/main/java/org/jabref/gui/util/DefaultTaskExecutor.java
@@ -19,6 +19,21 @@ public class DefaultTaskExecutor implements TaskExecutor {
 
     private static final Log LOGGER = LogFactory.getLog(DefaultTaskExecutor.class);
 
+    public static <V> V runInJavaFXThread(Callable<V> callable) {
+        FutureTask<V> task = new FutureTask<>(callable);
+        Platform.runLater(task);
+        try {
+            return task.get();
+        } catch (InterruptedException | ExecutionException e) {
+            LOGGER.error(e);
+            return null;
+        }
+    }
+
+    public static void runInJavaFXThread(Runnable runnable) {
+        Platform.runLater(runnable);
+    }
+
     @Override
     public <V> void execute(BackgroundTask<V> task) {
         new Thread(getJavaFXTask(task)).start();
@@ -54,16 +69,4 @@ private Exception convertToException(Throwable throwable) {
             return new Exception(throwable);
         }
     }
-
-    public static <V> V runInJavaFXThread(Callable<V> callable) {
-        FutureTask<V> task = new FutureTask<>(callable);
-        Platform.runLater(task);
-        try {
-            return task.get();
-        } catch (InterruptedException | ExecutionException e) {
-            LOGGER.error(e);
-            return null;
-        }
-    }
-
 }