The program checks the data integrity on program launch under certain conditions (that only the programmer knows).
Checking data integrity (on program launch anyway) doesn't necessarily indicate that there is a problem. It just indicates that certain conditions are present that increase the risk of problems, so the program double-checks the data.
Might have an anti-virus program or firewall tripping up the program on closing? Do you know what software is installed for anti-virus?
Is this an older machine or a rather new Windows 8 or 10?
Do you have a huge client database in Essential Forms?
Is your network/internet connection fast?
Our programmer built that check into the launch routine if certain conditions are present in the database to trigger it. One trigger possibly relevant is the size of the database. On top of that, on a slower network, that message will stay onscreen long enough for a user to notice it, whereas on a faster network it'll flash by.