Old known file DitExp.exe advised to sandbox

This file has been on my computer ages and is connected to a photocard.

Past 2 days Avast has been flagging up to put above-mentioned exe file in sandbox when husband opens Word 97 (yes, we know its old but lots of important files there). I have run both Avast and Malwarebytes and both passed as no bugs/viruses or malware in it.

How can I stop the message popping up. Only comes first time Word 97 is opened each day.

TIA

regards

Eve

Add the file to the autosandbox exceptions (File Shield > Expert Settings > AutoSandbox).