Thanks, that got me past the first hurdle. The next step I have in eliminating the problem of fie extension names having their left letter changed to an underscore is: “2 In the left part of the window, in the Anti-Virus protection section, select the Mail Anti-Virus subsection. In the right part of the window, the settings of the Mail Anti-Virus component are displayed” I did not see the first part but I did seethe second so I clicked on that. Now I have the mail Anti-Virus settings window open The next instruction is “4 In the Mail Anti-Virus window, select the Attachment filter tab.” I do not see an “Attachment filter tab” I am trying to follow the institutions in: https://support.kaspersky.com/KESWin/10SP2/en-US/128353.htm