Unsupported Compression Method

The current WinZip® version is WinZip 18.0 . You can obtain an evaluation copy of WinZip 18.0 from the WinZip download page.

If you received this message while extracting or testing files in a Zip file, one or more of the files is compressed using a method that is unknown to your version of WinZip.

WinZip 18.0 supports the following compression formats:

  • Enhanced deflate - Compression Method 9
  • bzip2 - Compression Method 12
  • WavPack - Compression Method 97
  • PPMd - Compression Method 98
  • LZMA - Compression Method 14
  • Jpeg compression - Compression Method 96
  • AES encryption - Compression Method 99

When this message is encountered, it is always possible that the Zip file is damaged. If possible, obtain a fresh copy of the file (e.g., by re-downloading it) and try again.

The compression methods that are currently defined by the Zip 2.0 standard are numbered from 0 to 10. WinZip supports methods 0 through 9, which are all of the methods that are fully documented and available for public use. The only method not supported is method 10, which is known as "DCL Implode." DCL Implode is a proprietary compression method that is typically used only in custom software and not in general-purpose Zip utilities. You will need other software to extract files compressed with DCL Implode.

Note: An 'Unsupported Compression Method' error will also appear:

  • If you have files compressed with WinZip 12 (or later) LZMA or Jpeg Compression and attempt to unzip the files with versions before WinZip 12 and WinZip Command Line Add-On 3.0.
  • If you have files compressed with WinZip 11 (or later) WavPack compression and attempt to unzip the files with versions before WinZip 11 and WinZip Command Line Add-On 2.3.
  • If you have files compressed with WinZip 10 (or later) PPMd compression and attempt to unzip the files with versions before WinZip 10 and WinZip Command Line Add-On 2.0.
  • If you have files compressed with WinZip 10 (or later) bzip2 compression and attempt to unzip the files with versions before WinZip 9 and WinZip Command Line Add-On 1.1.
  • If you have AES encrypted files with WinZip 9.0 (or later) and attempt to unzip the files with versions before WinZip 9 and WinZip Command Line Add-On 1.1.

If you encounter a compression method other than those listed above and are sure that your Zip file is undamaged, please contact help@winzip.com.