Item has already been added after upgrading Application Server


I have upgraded application server from version 2016.3 to 2016.11 and I am experiencing error - Item has already been added.

It is because caused by the duplicate files in your l10n folder.

We need to improve the error message.

That was the reason. When I copied new version, the AS Authorization files were still present in l10n folder and that caused the error. They were probably renamed as Security I guess?