Hi there, guys,
Can you please create a ticket on our support site with images of the error?
We will be able to investigate this further:
https://support.ubi.com/en-GB/faqs/0...isoft-Support/
- Cheers
Were you connected online when you did the upgrades? I had the same problem but I was offline. Didn't unlock for ages even though I tried other weapons. In the end, I had start a new game when connected line and redo it for the achievement to pop. For this game, you must always be connected online to ensure achievements unlock.