diff --git a/src/app/course/[courseName]/modules/[moduleName]/assignment/[assignmentName]/UpdateAssignmentName.tsx b/src/app/course/[courseName]/modules/[moduleName]/assignment/[assignmentName]/UpdateAssignmentName.tsx
index 07987c8..055c9ad 100644
--- a/src/app/course/[courseName]/modules/[moduleName]/assignment/[assignmentName]/UpdateAssignmentName.tsx
+++ b/src/app/course/[courseName]/modules/[moduleName]/assignment/[assignmentName]/UpdateAssignmentName.tsx
@@ -40,20 +40,25 @@ export function UpdateAssignmentName({
               if (name === assignmentName) closeModal();
 
               setIsLoading(true); // page refresh resets flag
-              await updateAssignment.mutateAsync({
-                assignment: assignment,
-                moduleName,
-                assignmentName: name,
-                previousModuleName: moduleName,
-                previousAssignmentName: assignmentName,
-                courseName,
-              });
+              try{
 
-              // update url (will trigger reload...)
-              router.replace(
-                getModuleItemUrl(courseName, moduleName, "assignment", name),
-                {}
-              );
+                await updateAssignment.mutateAsync({
+                  assignment: assignment,
+                  moduleName,
+                  assignmentName: name,
+                  previousModuleName: moduleName,
+                  previousAssignmentName: assignmentName,
+                  courseName,
+                });
+                
+                // update url (will trigger reload...)
+                router.replace(
+                  getModuleItemUrl(courseName, moduleName, "assignment", name),
+                  {}
+                );
+              }finally {
+                setIsLoading(false);
+              }
             }}
           >
             <TextInput
diff --git a/src/features/local/assignments/assignmentRouter.ts b/src/features/local/assignments/assignmentRouter.ts
index 86716d8..8bdf173 100644
--- a/src/features/local/assignments/assignmentRouter.ts
+++ b/src/features/local/assignments/assignmentRouter.ts
@@ -133,6 +133,18 @@ export async function updateOrCreateAssignmentFile({
   assignmentName: string;
   assignment: LocalAssignment;
 }) {
+  const illegalCharacters = ["<", ">", ":", '"', "/", "\\", "|", "?", "*"];
+  const foundIllegalCharacters = illegalCharacters.filter((char) =>
+    assignmentName.includes(char)
+  );
+  if (foundIllegalCharacters.length > 0) {
+    throw new Error(
+      `"${assignmentName}" cannot contain the following characters: ${foundIllegalCharacters.join(
+        " "
+      )}`
+    );
+  }
+
   const courseDirectory = await getCoursePathByName(courseName);
   const folder = path.join(courseDirectory, moduleName, "assignments");
   await fs.mkdir(folder, { recursive: true });