Data going missing

I have no idea why; nor even when, my laptop chooses to delete information on a patient file but it does so sporadically. Today I found out that the admitting diagnosis was not there on a patient that I had done prior to their move to another ward. It was easy as they had just one diagnosis but I have noted in the past that checkmarks were deleted after I considered that part of the patient file complete. Do I have a ghost in the machine or what?? Prior to marking things complete, I check to make sure that they are but apparently this does not matter. (as per Con 2013-07-30)