XLS file attachments to emails

Hello Bob.
We are sorry to hear about the inconvenience caused. MS Office files may contain what are called “Macro Viruses”. These files can run a “macro” (a macro is a mini-program run from within another program) that can be as destructive as any “regular” virus. So, our advice on MS Office attachments is not to open them unless you are expecting them. If they just show up, verify with the sender first. If it some unknown sender, please mark the sender as spam and do not open those attachments. Please, feel free to let us know if you require any further assistance. Thank you.

Hello Bob.
We are sorry to hear about the inconvenience caused. MS Office files may contain what are called “Macro Viruses”. These files can run a “macro” (a macro is a mini-program run from within another program) that can be as destructive as any “regular” virus. So, our advice on MS Office attachments is not to open them unless you are expecting them. If they just show up, verify with the sender first. If it some unknown sender, please mark the sender as spam and do not open those attachments. Please, feel free to let us know if you require any further assistance. Thank you.

I've been receiving a number of emails with .xls attachements - usually saying they are an invoice and generally from someone who is unidentifiable from the email address. AVG is not stopping the email but I'm very wary of opening the .xls file that's attached. Can .xls files harbour viruses?