apt - Trouble downloading packages list due to a "Hash sum mismatch" error - Ask Ubuntu

when check updates, "failed download repository information" error.

this comes under details:

w: failed fetch gzip:/var/lib/apt/lists/partial/us.archive.ubuntu.com_ubuntu_dists_natty_main_source_sources  hash sum mismatch,  e: index files failed download. have been ignored, or old ones used instead. 

just remove content of /var/lib/apt/lists directory:

sudo rm -rf /var/lib/apt/lists/* 

then run:

sudo apt-get update