many thanks for your honest and sincere reply. we have handled much of the error and crash vulnerabilities with log writing. First time when this particular issue came we analyzed our logs but found nothing. Second time we had told the client to enable doctor watson as the default debugger, so that we can analyse the drwatson log file to locate the fault point, but for this crash dr watson simply did not write anything. we have done drwatson debugging with other client sites and fixed the issues many time...so Third time we did more check up through out the code for any memory leaks but nothing significantly found. Now we have decided to run ProcessExplorer and get the dump file if this issue come again..(precisely to do this exercise in anticipation before the issue at client site we want to simulate and see whether ProcessExplorer dump file will help or not)