Rsync frequently hangs

[Brent Epp]

Hello,

I have a large collection of custom tooling that depends on rsync.  It 
used to work very well, but recently, rsync has become highly unstable.  
It frequently (dozens of times a day) hangs.  These are rsync executions 
where the source and target are both on the same local drive.

Eventually once it times out, it reports:

     rsync: connection unexpectedly closed (0 bytes received so far) 
[sender]
     rsync error: error in rsync protocol data stream (code 12) at 
io.c(226) [sender=3.1.2]

No changes have recently been made to the tooling.  I just upgraded 
cygwin as well, the problem persists.

I'm going to do a clean install of cygwin, but if that doesn't solve 
things, what else can I do?

  - Brent