I’ve generally found that unless you repeatedly get the message about it not being a recommended site, there's nothing to worry about, just try again in a few hours or the next day.
If your mirror site has not been listed for a day or so that means that some cygwin packages on your site are not current.
Check the cygwin-announce archives for announcements about recent package updates and ensure that your site has those packages.
Then drop the following batch file as Once you start the batch (e.g.
by double-clicking from Windows Explorer) it will download the latest installer from and perform a silent update.
I use Cygwin on my Windows machine to get access to all the wonderful Linux tools like grep, wget, etc.
One problem with Cygwin is you have to run it's GUI installer again manually each time you want to add tools or update the ones you already have.
As of March 1, 2016 Red Hat no longer sells the commercial Buyout License for Cygwin.
The commercial license is no longer necessary because Cygwin is now being distributed under the GNU Lesser GPL (LGPL).
apt-cyg provides a command-line package manager that you can use to install tools without using the GUI installer.
However, I didn't see a way to update the existing tools.
This article describes how to upgrade your Cygwin GCC installation to a more recent version (e.g., 4.6.1).