close failed in file object destructor:

[timnewsham]

I installed on ubuntu 16.04.3 server and followed the startup instructions in the readme to load the vulnerable test driver in the guest and start fuzzing it. After about three minutes the UI displays a python error

close failed in file object destructor: IOError: [Errno 9] Bad file descriptor

It does not provide much context and the fuzzer process seems to continue running.