Client task does not close properly after doing exports

Not a crash, but a stability issue. I periodically export all of my mail and contacts, so that I will have it in a neutral format in case eM Client were to suddenly become unusable (as happened to me with Windows Live Mail). Sometimes (often), the morning after the day in which I did the exports, the client fails to open. When this happens, the Task Manager shows an eM Client process running. (I always close the client after each session.) Ending that process allows the client to open, but it then spends a lot of time checking the integrity of the database, having detected an improper shutdown. I can always close and re-open the client soon after doing the exports, without problems. And I sense that if I open and close the client multiple times that same day, the problem does not occur the next morning. The problem always occurs first thing in the morning, and it only happens on a day after I had done exports. I can think of no other pattern.