A BAD DELETE?

[JimT]

I was never a compression guru, but from what I remember there are number of different compression algorithms out there. Typical windows zip utilities can only handle pkzip. 7-Zip on the other hand can handle other algorithms such as bzip/bzip2 and lzma/lzma2. So yes, if you're using windows just get 7-zip for all your compression needs.

Edit:
From the 7zip wikipedia entry:

Quote:7-Zip supports a number of other compression and non-compression archive formats (both for packing and unpacking), including ZIP, gzip, bzip2, xz, tar, and WIM. The utility also supports unpacking APM, ar, ARJ, chm, cpio, deb, FLV, JAR, LHA/LZH, LZMA, MSLZ, Office Open XML, onepkg, RAR, RPM, smzip, SWF, XAR, and Z archives and cramfs, DMG, FAT, HFS, ISO, MBR, NTFS, SquashFS, UDF, and VHD disk images.

Conclusion: 7zip can handle unpacking just about anything you throw at it.