https://bugs.winehq.org/show_bug.cgi?id=53439
--- Comment #1 from Joel Holdsworth joel@airwebreathe.org.uk --- The Z drive contains Wine's representation of the host UNIX file system. In msys2 this appears as /z/.
As far as I can tell, every msys2 shell command fails if it involves the Z drive with an "Input/output error"