Excel suddenly asking for workbook encryption password 2X after it has been opened

[toddbrannon]

I have a password encrypted workbook that I have been working with for several months now. All of the sudden in the past several days, once I enter the password to open it, it requests the password twice more. I can cancel both requests and begin working in the file with no issues. It's just annoying that it is doing this. Does anybody have any idea what would cause this behavior?

Thanks in advance!