Thanks Joe. I will call in, but if you could show this post to the 75xx guys also I'd appreciate it!
Applying the patch does not disable SMB1, so wouldn't break Workflow Scanning. While the patch protects against WannaCry, SMB1 is a very old (30 years) and insecure protocol, and Microsoft recommends disabling it completely. Here's a blog from the SMB owner at Microsoft explaining why:
https://blogs.technet.microsoft.com/filecab/2016/09/16/stop-using-smb1/
Disabling SMB1 for testing in a lab environment is easy. Just import this registry setting and then restart the Server service and SMB1 will be off. Delete the key or change it to 1 and restart the service to re-enable.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters] "SMB1"=dword:00000000
From my Wireshark captures, it's clear that the 75xx is only advertising SMB1 support. If the code is there for SMB2, it isn't fully implemented. So when SMB1 is disabled on the server, Workflow Scanning can't talk to the server. Or, in a more strict sense, the server sees the copier only supports SMB1 and refuses to talk to it.
Thanks again! Fingers crossed for a SPAR update soon.
Tom