可以尝试删除resumeData文件或者使用如下代码处理该错误：

Alamofire.download(urlString, to: destination)
    .downloadProgress { progress in
        print("当前下载进度: \(progress.fractionCompleted)")
    }
    .responseData { response in
        if let error = response.error, let resumeData = error.userInfo[NSURLSessionDownloadTaskResumeData] as? Data {
            let downloadRequest = Alamofire.download(resumingWith: resumeData, to: destination)
            downloadRequest.downloadProgress { progress in
                print("继续下载进度: \(progress.fractionCompleted)")
            }
            downloadRequest.responseData { response in
                debugPrint(response)
            }
        } else {
            debugPrint(response)
        }
}

其中，将错误转换为resumeData，通过Alamofire的resume方法恢复下载，最后获取responseData。