You need to follow up

Boss: Have you ever finished project x?  I forgot to follow up with you and you never get back to me about the status.  In the future, you need to let me know.

Me: I sent you the project x files on Friday. I forwarded that email to you in this one. You probably missed it.

The email was even time stamped on Friday.

Boss: I only see Thursday. (I didn't even send anything to her on Thursday!)  Did you not make any update on Friday?

Me: The date on the file shows it was completed on Friday.

Boss: Next time put the file in the date you made it so we are not confused.
Because looking at the date of the file or email that it was in is too intelligent.