Started getting this on Enterprise Edition about an hour ago:
100% [Packages 7,589 kB]100% [Packages 7,589 kB]Fetched 3,459 kB in 5s (586 kB/s)
W: Size of file /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty-updates_restricted_binary-amd64_Packages.gz is not what the server reported 21099 21216
W: Size of file /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty-updates_multiverse_binary-amd64_Packages.gz is not what the server reported 15541 15575
W: Size of file /var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_restricted_binary-amd64_Packages.gz is not what the server reported 17782 17859
W: Size of file /var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_multiverse_binary-amd64_Packages.gz is not what the server reported 3999 4015
W: Size of file /var/lib/apt/lists/ppa.launchpad.net_openjdk-r_ppa_ubuntu_dists_trusty_main_binary-amd64_Packages.gz is not what the server reported 4396 7564
W: Size of file /var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-amd64_Packages.gz is not what the server reported 1133 1140
W: Failed to fetch https://packagecloud.io/basho/riak/ubuntu/dists/trusty/main/source/Sources HttpError401
W: Failed to fetch https://packagecloud.io/basho/riak/ubuntu/dists/trusty/main/binary-amd64/Packages HttpError401
E: Some index files failed to download. They have been ignored, or old ones used instead.
sudo apt-get update returned exit code 100
Action failed: sudo apt-get update