My company has a licensed Exch 2010 std edition installed on a rack server and that also contains the DC. Recent past I built up another server (basically a secondary DC + Exch 2010). I was able to connect the servers, replicate the AD objects and Exch Users mailbox, all came fine. (Note: the secondary server has the trial version of Exch 2010 std.) I removed the secondary server as I was needing it for some other purpose. What happened now is, whenever I open the EMC (the primary one) , I get to see a dialogue box asking me to enter the product key and this is pointing to secondary server which is no longer connected. How will I get rid of the issue? The primary Exch has no problem and its working fine, but when i click on the Server Config, I see 2 Exch server (1 is the licensed and working; 2 trial version came from the secondary server). The trial version which will expire in 120 days, will it cause any problem to the primary server after 120 days?

regards

Uninstall Exchange from the old server while it is connected.  If you destroyed that server before uninstalling Exchange, the only supported method for resolving the problem is to build a new server with the same name, install Exchange on it with the setup.com /Mode:RecoverServer switch, and then uninstalling it running setup.com /Mode:Uninstall.

The expiry won't cause any problems except you being nagged about it.  However having that server still in AD may cause any sorts of problems down the road, so I recommend that you follow my advice and remove it cleanly.