Hello,
I have posted a couple of threads for help with Excel, which I am pretty familiar with. I am however at a new job, with a Mac. I have tried attaching sample workbooks, with the same error: "Unable to attach file- invalid file". They were .xls files, and less than 1000KB. It was suggested that I zip the files, which worked...but the forum moderator said it appeared as only a text file.

Am I doing something wrong, or is it possibly a Mac thing?

Anyone with Mac experience, let me know if I need to do something differently to attach my sample workbooks on this forum.

Thanks so much for the help.