When you first install cygwin and run bash, it’ll usually display this error message:
Your group is currently "mkpasswd". This indicates that
the /etc/passwd (and possibly /etc/group) files should be rebuilt.
See the man pages for mkpasswd and mkgroup then, for example, run
mkpasswd -l [-d] > /etc/passwd
mkgroup -l [-d] > /etc/group
Note that the -d switch is necessary for domain users.
While I’m on the subject of Cygwin hacking, I discovered this man-page about the Cygwin X server: type
man XWinrc and read about how you can hack your systray icon to include a little launcher menu for you favorite X clients 8)
I don’t know why I haven’t ever got around to this, but here—finally—is a hack to have Cygwin only ever start one instance of emacs (especially important in cygwin, because Win32 does not appear to share program texts between processes… )