diff --git a/apps/red-ui/src/app/modules/dossier/screens/dossier-overview/components/screen-header/screen-header.component.ts b/apps/red-ui/src/app/modules/dossier/screens/dossier-overview/components/screen-header/screen-header.component.ts
index 7637b5574..c4b737133 100644
--- a/apps/red-ui/src/app/modules/dossier/screens/dossier-overview/components/screen-header/screen-header.component.ts
+++ b/apps/red-ui/src/app/modules/dossier/screens/dossier-overview/components/screen-header/screen-header.component.ts
@@ -69,7 +69,7 @@ export class ScreenHeaderComponent implements OnInit {
             const fileName = this.dossier.dossierName + '.export.csv';
             const mapper = (file?: IFile) => ({
                 ...file,
-                assignee: this._userService.getNameForId(file.assignee),
+                assignee: this._userService.getNameForId(file.assignee) || '-',
                 primaryAttribute: this._primaryFileAttributeService.getPrimaryFileAttributeValue(file, this.dossier.dossierTemplateId),
             });
             const fileFields = [
diff --git a/apps/red-ui/src/app/services/user.service.ts b/apps/red-ui/src/app/services/user.service.ts
index c610856bc..7a0417975 100644
--- a/apps/red-ui/src/app/services/user.service.ts
+++ b/apps/red-ui/src/app/services/user.service.ts
@@ -125,6 +125,9 @@ export class UserService extends EntitiesService<User, IUser> {
         if (id?.toLowerCase() === 'system') {
             return new User({ username: 'System' }, [], 'system');
         }
+        if (!id) {
+            return undefined;
+        }
         return super.find(id) || new User({ username: 'Deleted User' }, [], 'deleted');
     }
 }