Problem exporting (reconverting) a file worked on Studio 2014 (with .xlf extension converted into xliff) to upload it to the same website it came from.

I imported a big file from an online translation system that works with Wordbee with an .xlf extension in order to translate it in Studio 2014. After reaching 2000 segments I tried to Export it to upload it to the client website, and it gives me this error:

Collection was modified; enumeration operation may not execute.

I really don't know what to do. Can you please help.