diff --git a/src/main/java/de/uni_hamburg/corpora/gui/GUI.java b/src/main/java/de/uni_hamburg/corpora/gui/GUI.java
index cafc5dea16f3b0b4aba8d18bebd16bd5c893a2f1..c48e0b413ed579e0e7d8ac64f34a91524a4b236f 100644
--- a/src/main/java/de/uni_hamburg/corpora/gui/GUI.java
+++ b/src/main/java/de/uni_hamburg/corpora/gui/GUI.java
@@ -160,6 +160,14 @@ public class GUI {
         });
         mainPanel.add(buttonPanel);
         window.getContentPane().add(mainPanel);
+        if (!new File("corpus-services.jar").exists()) {
+            checkButton.setEnabled(false);
+            JOptionPane.showMessageDialog(window,
+                    "Corpus services file corpus-services.jar is missing. Before you can use this application"
+                    + " you have to update Corpus services using the button below.",
+                    "Warning",
+                    JOptionPane.WARNING_MESSAGE);
+        }
     }
 
     /**