diff --git a/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/attributes/prettyPrint/PrettyUtils.java b/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/attributes/prettyPrint/PrettyUtils.java
index 3cb3883bd..c55e6d247 100644
--- a/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/attributes/prettyPrint/PrettyUtils.java
+++ b/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/attributes/prettyPrint/PrettyUtils.java
@@ -2,8 +2,10 @@
 
 import de.peeeq.wurstio.WurstCompilerJassImpl;
 import de.peeeq.wurstscript.RunArgs;
+import de.peeeq.wurstscript.ast.Ast;
 import de.peeeq.wurstscript.ast.CompilationUnit;
 import de.peeeq.wurstscript.ast.Element;
+import de.peeeq.wurstscript.ast.WurstModel;
 import de.peeeq.wurstscript.gui.WurstGui;
 import de.peeeq.wurstscript.gui.WurstGuiCliImpl;
 import org.apache.commons.lang.StringUtils;
@@ -40,7 +42,13 @@ public static void pretty(List<String> args) throws IOException {
     }
 
     public static String pretty(String source, String ending) {
-        CompilationUnit cu = parse(source, ending);
+        WurstGui gui = new WurstGuiCliImpl();
+        CompilationUnit cu = parse(source, ending, gui);
+        
+        // Check for compilation errors before pretty printing
+        if (gui.getErrorCount() > 0) {
+            throw new RuntimeException("Cannot format code with compilation errors:\n" + gui.getErrors());
+        }
 
         Spacer spacer = new MaxOneSpacer();
         StringBuilder sb = new StringBuilder();
@@ -50,11 +58,25 @@ public static String pretty(String source, String ending) {
     }
 
     private static void prettyPrint(String filename) {
-        String clean = pretty(filename, filename.substring(filename.lastIndexOf(".")));
-        System.out.println(clean);
+        try {
+            String clean = pretty(filename, filename.substring(filename.lastIndexOf(".")));
+            System.out.println(clean);
+        } catch (RuntimeException e) {
+            System.err.println("Error formatting " + filename + ": " + e.getMessage());
+            throw e;
+        }
     }
 
     public static void pretty(CompilationUnit cu) {
+        pretty(cu, new WurstGuiCliImpl());
+    }
+    
+    public static void pretty(CompilationUnit cu, WurstGui gui) {
+        // Check for compilation errors before pretty printing
+        if (gui.getErrorCount() > 0) {
+            throw new RuntimeException("Cannot format code with compilation errors:\n" + gui.getErrors());
+        }
+        
         Spacer spacer = new MaxOneSpacer();
         StringBuilder sb = new StringBuilder();
         cu.prettyPrint(spacer, sb, 0);
@@ -64,7 +86,13 @@ public static void pretty(CompilationUnit cu) {
 
     private static void debug(String filename) {
         String contents = readFile(filename);
-        CompilationUnit cu = parse(contents, filename.substring(filename.lastIndexOf(".")));
+        WurstGui gui = new WurstGuiCliImpl();
+        CompilationUnit cu = parse(contents, filename.substring(filename.lastIndexOf(".")), gui);
+        
+        // Check for compilation errors before debugging
+        if (gui.getErrorCount() > 0) {
+            throw new RuntimeException("Cannot debug code with compilation errors:\n" + gui.getErrors());
+        }
 
         walkTree(cu, 0);
     }
@@ -91,7 +119,13 @@ private static void prettyAll(String root) throws IOException {
 
     private static String pretty(File f) {
         String contents = readFile(f.toString());
-        CompilationUnit cu = parse(contents, f.getName().substring(f.getName().lastIndexOf(".")));
+        WurstGui gui = new WurstGuiCliImpl();
+        CompilationUnit cu = parse(contents, f.getName().substring(f.getName().lastIndexOf(".")), gui);
+        
+        // Check for compilation errors before pretty printing
+        if (gui.getErrorCount() > 0) {
+            throw new RuntimeException("Cannot format code with compilation errors:\n" + gui.getErrors());
+        }
 
         Spacer spacer = new MaxOneSpacer();
         StringBuilder sb = new StringBuilder();
@@ -119,7 +153,24 @@ private static String readFile(String filename) {
 
     private static CompilationUnit parse(String input, String ending) {
         WurstGui gui = new WurstGuiCliImpl();
+        return parse(input, ending, gui);
+    }
+    
+    private static CompilationUnit parse(String input, String ending, WurstGui gui) {
         WurstCompilerJassImpl compiler = new WurstCompilerJassImpl(null, gui, null, new RunArgs("-prettyPrint"));
-        return compiler.parse("format" + ending, new StringReader(input));
+        CompilationUnit cu = compiler.parse("format" + ending, new StringReader(input));
+        
+        // Create a minimal model to run validation
+        WurstModel model = Ast.WurstModel();
+        model.add(cu);
+        
+        // Run validation to detect compilation errors
+        try {
+            compiler.checkProg(model);
+        } catch (Exception e) {
+            // Errors are already added to gui during validation
+        }
+        
+        return cu;
     }
 }
diff --git a/de.peeeq.wurstscript/src/test/java/tests/prettyprint/PrettyPrintErrorTest.java b/de.peeeq.wurstscript/src/test/java/tests/prettyprint/PrettyPrintErrorTest.java
new file mode 100644
index 000000000..b4bdfd8fe
--- /dev/null
+++ b/de.peeeq.wurstscript/src/test/java/tests/prettyprint/PrettyPrintErrorTest.java
@@ -0,0 +1,37 @@
+package tests.prettyprint;
+
+import de.peeeq.wurstscript.attributes.prettyPrint.PrettyUtils;
+import org.testng.annotations.Test;
+import tests.wurstscript.tests.WurstScriptTest;
+
+import static org.testng.AssertJUnit.fail;
+
+public class PrettyPrintErrorTest extends WurstScriptTest {
+
+    @Test
+    public void testPrettyPrintFailsWithCompilationErrors() {
+        String invalidCode = "package TestInvalid\n\nfunction test()\n    undefinedFunction()\n    let x = undefinedVariable";
+        
+        try {
+            String result = PrettyUtils.pretty(invalidCode, ".wurst");
+            fail("Expected RuntimeException for code with compilation errors, but pretty printing succeeded");
+        } catch (RuntimeException e) {
+            // Expected behavior - pretty printer should fail with compilation errors
+            assert e.getMessage().contains("Cannot format code with compilation errors");
+        }
+    }
+    
+    @Test
+    public void testPrettyPrintSucceedsWithValidCode() {
+        String validCode = "package TestValid\n\nfunction test()\n    print(\"Hello World\")";
+        
+        try {
+            String result = PrettyUtils.pretty(validCode, ".wurst");
+            // Should succeed without throwing an exception
+            assert result != null;
+            assert result.contains("package TestValid");
+        } catch (Exception e) {
+            fail("Pretty printing valid code should not throw an exception: " + e.getMessage());
+        }
+    }
+}
\ No newline at end of file