Suppressing Msgboxes Appearing During Loop

Basically upon opening my workbook, I have some code that runs to loop through all the sheets and make certain sheets visible based upon which password the user enters. However, I also have some code upon activation of some of these sheets to have a msgbox pop up explaining what the sheet is about. I obviously dont want these to appear when the initial loops is going through activating the sheets one by one - I only want these msgboxes to appear when the user subsequently opens one of these sheets.