Shared workbooks
 

I have a reporting system that consists of shared workbooks with
approximately 30 users. The files are set to automatically save when they
are closed. There are not usually any conflicts because each user has their
own section that they enter data into. Sometimes, however when a user enters
their data and then reopens the file the data is gone. I have looked
everywhere trying to figure out why this is happening, but I cannot find
anything. Does anyone have any idea what's causing this and if it can be
avoided?