Since some time, I have been unable to upload packages to Hackage, via either the 'cabal upload' command, or using the web form. The error message it gives is this: ==== ✂ ==== Hackage username: AriePeterson Hackage password: Uploading dist/np-linear-0.1.1.1.tar.gz... Error: dist/np-linear-0.1.1.1.tar.gz: 400 Bad Request Error: Invalid package Invalid windows file name in tar archive: "np-linear-0.1.1.1\\src\\Aux.hs". For portability, hackage requires that file names be valid on both Unix and Windows systems, and not refer outside of the tarball. ==== ✂ ==== The tarball is created by 'cabal sdist': cabal-install version 1.18.0.2 using version 1.18.1.1 of the Cabal library. I also installed the newest cabal-install, on another machine, but this did not help (same error). I also tried to create a tarball by hand, using 'tar --format=ustar', but this again resulted in the same error message. By the way, I'm on linux, not Windows, so it is not clear how the backslashes get in the file names. What could be going on?