If your message processing regions for an enterprise server become unresponsive for some reason you need to perform a cold start. Performing a cold start involves deleting the IMS message queue for an enterprise server, so any outstanding messages are lost and need to be resubmitted after the cold start.
To perform a cold start you delete the file %USERPROFILE%\Documents\Micro Focus\Net Express x.x\WORKAREA \ES_name\imsmesgq.dat, where ES_name is the name of the enterprise server whose message processing regions are unresponsive.