diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify2Task.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify2Task.java
index 46af7349..b3884e07 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify2Task.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify2Task.java
@@ -39,12 +39,17 @@ public class TypeUnify2Task extends TypeUnifyTask {
                        return new HashSet<>(); }
                else
                */ 
-               if (this.isCancelled()) {
-       			return new HashSet<>();
-       		   }
+
                noOfThread--;
-               return res;
-       }
+               synchronized (usedTasks) {
+            	   if (this.myIsCancelled()) {
+   						return new HashSet<>();
+   					}
+   					else {
+   						return res;
+   					}
+   				}
+       	}
        
        public void closeLogFile() {
 
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index 36a2bc43..f6bf6a4e 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -122,6 +122,8 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 	
 	static Integer  noShortendElements = 0;
 	
+	Boolean myIsCanceled = false;
+	
 	volatile UnifyTaskModel usedTasks;
 	
 	public TypeUnifyTask() { 
@@ -170,13 +172,19 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			thNo = totalnoOfThread;
 			writeLog("thNo2 " + thNo);
 			try {
-				this.logFile = new OutputStreamWriter(new NullOutputStream());
-				//new FileWriter(new File(System.getProperty("user.dir")+"/src/test/java/logFiles/"+"Thread_"+thNo));
+				this.logFile = //new OutputStreamWriter(new NullOutputStream());
+				new FileWriter(new File(System.getProperty("user.dir")+"/src/test/java/logFiles/"+"Thread_"+thNo));
 				logFile.write("");
 			}
 			catch (IOException e) { 
 				System.err.println("log-File nicht vorhanden");
 			}
+			if (thNo > 10) {
+				System.out.println("cancel");
+				usedTasks.cancel();
+				writeLog(nOfUnify.toString() + "cancel");
+				System.out.println("cancel");
+			}
 			rules = new RuleSet(logFile);
 			this.rekTiefeField = rekTiefe;
 			this.urm = urm;
@@ -217,6 +225,13 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		}		
 }
 */
+	void myCancel(Boolean b) {
+		myIsCanceled = true;
+	}
+	
+	public boolean myIsCancelled() {
+		return myIsCanceled;
+	}
 	
 	protected Set<Set<UnifyPair>> compute() {
 		if (one) {
@@ -232,9 +247,6 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				.filter(x -> x.size()>1)
 				.collect(Collectors.toCollection(ArrayList::new));
 		Set<Set<UnifyPair>> res = unify(neweq, remainingOderconstraints, fc, parallel, rekTiefeField, true);
-		if (this.isCancelled()) {
-			return new HashSet<>();
-		}
 		noOfThread--;
 		try {
 			logFile.close();
@@ -245,7 +257,16 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		if (isUndefinedPairSetSet(res)) { 
 				throw new TypeinferenceException("Unresolved constraints: " + res.toString(), new NullToken()); //return new HashSet<>(); 
 			}
-		else return res;
+		else {
+			synchronized (usedTasks) {
+				if (this.myIsCancelled()) {
+					return new HashSet<>();
+				}
+				else {
+					return res;
+				}
+			}
+		}
 	}
 /*	
 	@Override
@@ -279,9 +300,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		/*
 		 * Step 1: Repeated application of reduce, adapt, erase, swap 
 		 */
-		if (totalnoOfThread > 10) {
-			usedTasks.cancel();
-		}
+		
 		rekTiefe++;
 		nOfUnify++;
         writeLog(nOfUnify.toString() + " Unifikation: " + eq.toString());
@@ -820,7 +839,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
 				//forks.add(forkOrig);
 				synchronized(usedTasks) {
-					if (this.isCancelled()) {
+					if (this.myIsCancelled()) {
 						return new HashSet<>();
 					}
 					forkOrig.fork();
@@ -872,7 +891,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 					TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
 					forks.add(fork);
 					synchronized(usedTasks) {
-						if (this.isCancelled()) {
+						if (this.myIsCancelled()) {
 							return new HashSet<>();
 						}
 						fork.fork();
@@ -923,7 +942,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
 				//forks.add(forkOrig);
 				synchronized(usedTasks) {
-					if (this.isCancelled()) {
+					if (this.myIsCancelled()) {
 						return new HashSet<>();
 					}
 					forkOrig.fork();
@@ -975,7 +994,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 					TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
 					forks.add(fork);
 					synchronized(usedTasks) {
-						if (this.isCancelled()) {
+						if (this.myIsCancelled()) {
 							return new HashSet<>();
 						}
 						fork.fork();
@@ -1027,7 +1046,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		    	TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
 		    	//forks.add(forkOrig);
 		    	synchronized(usedTasks) {
-					if (this.isCancelled()) {
+					if (this.myIsCancelled()) {
 						return new HashSet<>();
 					}
 					forkOrig.fork();
@@ -1048,7 +1067,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		    		TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
 		    		forks.add(fork);
 		    		synchronized(usedTasks) {
-						if (this.isCancelled()) {
+						if (this.myIsCancelled()) {
 							return new HashSet<>();
 						}
 						fork.fork();
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java
index 2cc0d7d4..5b70eff8 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java
@@ -12,7 +12,7 @@ public class UnifyTaskModel {
     
     public void cancel() {
     	for(TypeUnifyTask t : usedTasks) {
-    		t.cancel(true);
+    		t.myCancel(true);
     	}
     }
 }