Your log shows that apt-get is requesting only the .xz form of Packages files. Approx only works with gzip-compressed files (since it needs to decompress and recompress on the fly, and the other formats are too slow for that). The default configuration of apt will "fall back" to gzip after first trying bz2 and lzma.
Do you have any settings in your apt.conf or apt.conf.d/* files that change the Acquire::CompressionTypes values to use only xz? -- Eric Cooper e c c @ c m u . e d u -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org