Customers will occasionally report an error similar to this when running a layer 2 scan.

"Could not start extension."

"The InterMapper Server cannot connect to the desired extension at The extension service is not responding."

This can be resolved by the following.

Please delete InterMapper_Settings/Extensions/com.dartware.switches/ file and relaunch intermapperd.

If that does not help you will need to reboot the system.

Note: Intermapper Settings can be found here per OS.