Who Changed that setting?

I frequently have clients call and ask "How can I tell who changed that setting". One answer is to to turn on activity tracking in system settings (Tools>>setup>>system>>activity tracking). You have some simple functions you can track such as login failures, changes to setup files, changes to card maintenance files etc.

After turning on the fuction you can then generate reports to see the activities you are tracking under Reports>>system>>general>>activity detail.

This is not a very robust tool but can give you information such as user who made changes, date and time, workstation ID, etc. A good start and doesn't cost any money to implement.

For more comprehensive tools you would have to purchase the MBS Auditor module or a third party product such as Rocktons Auditor.

So, I would suggest starting with Activity Tracking as a nice and simple first step.