​The other day I was working with a client setting up the UPS
Connection to their Active Directory.Everything was going fine until we tried to expand the Active Directory
tree to select the appropriate Organizational Units to synchronize.

We would click to expand it, and ever about 5 minutes we
would receive an error stating, The
operation was aborted because the client side timeout limit was exceeded.
We attempted to increase the timeout values
according to this article on TechNet – http://technet.microsoft.com/en-us/library/ff681014.aspx#timeouts.

No matter how high we increased the timeout value, we
continued to receive the error after about 5 minutes.After continuing to search for answers, we
ran across this string in the SharePoint Forums – http://social.technet.microsoft.com/Forums/en/sharepoint2010setup/thread/3ffb5c99-176f-425e-9409-0fbb6762bf17.The solution to our problem was to open the
Local Computer Policy on the server running UPS and browse to Computer ConfigurationWindows
SettingsSecurity SettingsLocal PoliciesSecurity Options
and set network security:LDAP client signing
requirements
to none.

editGPO.jpg

Once you’ve made this change, restart the two UPS Services
in the Services on Server in your SharePoint Central Administration.

Once this has been done, you should be able to go back into
your UPS connections and expand the Active Directory tree to pick the appropriate
Organization Units for your synchronization connection.