I'm getting an error message: "unsupported compression method 98" when unzipping a file somebody sent to me. I've tried both an older version of WinZip, and 7-Zip 4.65.

(Update: I've also tried Windows own built-in Compressed Folders to open the archive (on Windows 7), but it reports Unspecified Error 0x80004005 on the archive. Presumably, that means Windows itself doesn't support this compression method, either.)

I've already asked the person to avoid using a non-standard compression method and re-send the file. I know WinZip (of which they are using a newer version) has compatibility options. But, I'm wondering:

What archiving utilities, other than WinZip, support this "compression method 98"?

In particular, is there a free and/or open source tool that supports that method? If not, why not? Is the method strictly proprietary to WinZip?


Try 7zip 9.14. 7zip beta's are like other software in stable, so don't worry.

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  • Confirmed: 7-Zip 9.14 can unarchive compression method 98 (PPMd) ZIP archives. Thank you – Chris W. Rea Jun 9 '10 at 14:41

one of those




I Highlight PKZIP and UHARC


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  • Thanks, but do you have knowledge that those tools specifically support "compression method 98", also known as PPMd ? I'm not looking for simply any alternative to WinZip, but one that specifically supports "compression method 98". – Chris W. Rea Jun 9 '10 at 14:30

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