I have a small test script reproducing the problem
// include Fake lib
#r @"tools\FAKE\tools\FakeLib.dll"
open Fake
let root = @"\\wgprintsrv\FTP\FTPSoftware\FTPSW\weincad\release"
let glob = root @@ "**\*.dll"
trace glob
!! glob
|> Seq.iter (fun file -> trace file )
it lists nothing. Just to check the following powershell command
ls -R \\wgprintsrv\FTP\FTPSoftware\FTPSW\weincad\release -Filter *.dll
generates everything I expect. If I replace the UNC path with a local relative path then everything works. Is this possible to work around or is it a core problem with UNC paths and F# globbing?