I have the same problem with Windows 10 64 bit, the error log is as follows: Parameter name: codepage at System.Text.Encoding.GetEncoding(Int32 codepage) at ICSharpCode.SharpZipLib.Zip.ZipFile.ReadEntries() at ICSharpCode.SharpZipLib.Zip.ZipFile..ctor(String name) at NAPS2.Dependencies.DownloadFormat.ZipDownloadFormat.Extract(String zipFilePath, String outDir) at NAPS2.Dependencies.DownloadFormat.ZipDownloadFormat.Prepare(String tempFilePath) at NAPS2.WinForms.FDownloadProgress.StartNextDownload()...