Shared folders missing after Windows 10 Anniversary Update

[jorgensen]

After installing the Windows 10 Anniversary Update, the \\Vboxsvr was missing in the network locations.
A new installation of the Guest Additions solved this.
Current Virtualbox version was 5.1.2

[scottgus1]

I have run into Anniversary Update not having all my previously-installed programs there, one or two got missed, or not installed properly & requiring a re-install. I think AU is a complete or at least partial reinstall of the whole OS, and requires re-install, automatic or otherwise, of the programs. I'm keeping this in mind for the next anniversary.