ubuntu update,
failed to download repository information;
sudo apt-get clean sudo apt-get update sudo apt-get upgrade
If you still have issues, then change your repo mirror: Open Update Manager or Software Updater, then click Settings > Ubuntu Software tab, then select Other from the Download From menu and click the Select Best Server button. Now try updating/upgrading again.
参考:https://askubuntu.com/questions/141512/how-to-resolve-failed-to-download-repository-information