There are places where WT checks for POSIX error numbers (like ENOENT) that are being returned from OS level system calls. Assuming POSIX errnos does not translate on Windows. We need a translation layer. One such is https://hackage.haskell.org/package/base-4.3.0.0/src/cbits/Win32Utils.c or https://github.com/hyc/BerkeleyDB/blob/master/src/os_windows/os_errno.c.