something wrong

We have an accounting package called business works.In that,very recently, the accountant did certain transactions, but didn’t get updated where all it was suppose to update. To check if there was a problem with the program I made a dummy entry and checked. At that time it was correctly updating all the places it was suppose to update.Then I asked him if he had to abruptly shut down his PC, but he said that he doesn’t remember.I want to know what would have been the problem and how to avoid this in the future.