Status: Exhausted Bitcoin Wallet Passphrase Recovery

[Mem5]

Bitcoin wallet & 15 chars is not doable in a human life.

By the way your problem is the last '?' character, remove it :

C:\Users\wq\Desktop\hashcat-4.1.0>hashcat64.exe -a 3 -m 11300 wallethash.txt ?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?a?

Finally hashcat-4.1.0 is outdated. Use v5.1.0