The answer is Yes.

You have the setting under Setup, Reports & Forms, Form Data Export checked to Export CSV files when printing forms from data entry screens in Sage 50.  The invcust.csv and about 6 other files are used for Customer Quotes, Orders and Invoices.  People use this setting when they want to continue using older Crystal Reports templates with Sage 50 or are using the csv files for other programs.

Each time you print the series of files are updated.  When you close the program they are deleted (if you are using a version 2015 or higher I believe).

These files are found in

C:\Users\WindowsUserName\Documents\Simply Accounting\forms\CANxxxx

where Windows User Name is the name you are logged into Windows as (this is the personal My Documents folder), and xxxx is the year of the version of Sage 50 you are using.

Looks like AVG doesn't like you changing My Documents files, so you will have to exclude the folder above from it's list of places to protect.

thank you Richard