I am migrating some TB of data from a user's mail box to multiple psts. I have written a tool to automate this process. this tool reads all the mails from inbox, and moves them to pst. No body is using these mail boxes i am workin on. Some times, during process, i get a pop up that "Custom form could not be opened. Outlook will use an Outlook form instead. The object does not support the requested action." and as soon as i click on the ok button, i see that outbox folder has a message.and suddenly it goes away. I checked the sent item folders and there is no mail sent from this mail box. Because of this pop up, this process gets paused untill i click on OK button. this is kind of starange behavior and i am not able to figure it out.If anybody has some information, please let me know.