Ubuntu Xenial - apt update - E: Some index files failed to download. They have been ignored, or old ones used instead.

Recently, I installed Ubuntu 16.04 on a new PC and updated my repository URLs in "/etc/apt/sources.list" file to point to internal Ubuntu repository servers.


While I was updating my package indexes, I encountered the following errors:

E: Failed to fetch http://repo.xxx.xxx.in/ubuntu/dists/xenial/main/i18n/Translation-en  404  Not Found
E: Failed to fetch http://repo.xxx.xxx.in/ubuntu/dists/xenial-updates/main/i18n/Translation-en  404  Not Found
E: Failed to fetch http://repo.xxx.xxx.in/ubuntu/dists/xenial-backports/main/i18n/Translation-en  404  Not Found
E: Failed to fetch http://repo.xxx.xxx.in/ubuntu/dists/xenial-security/main/i18n/Translation-en  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

After searching on google and stackoverflow, it seems a language translation issue. To get rid of this issue, please follow the following steps:

1) Create a file named /etc/apt/apt.conf.d/99translations & add the following content to it:

Acquire::Languages "none";

2) You may also need to remove existing translation files in /var/lib/apt/lists/
$ sudo rm -vf /var/lib/apt/lists/*

3) Now, do cleanup and update of package indexes.

$ sudo apt-get clean
$ sudo apt-get update

Some useful references on stackoverflow:
1) https://askubuntu.com/questions/74653/how-can-i-remove-the-translation-entries-in-apt
2) https://askubuntu.com/questions/762273/16-04-upgrade-failed-to-fetch-empty-files-cant-be-valid-archives/764463