What is the proper filing protocol for m and mc and filing alphabet and numerical

All the offices where I have worked have just treated the small "c" as the second letter in the word with no special treatment.

I suppose as an alternative you could file all the Ms - Ma through Mz, then start over with McA names through McZ. It doesn't really matter except that you have to have consistency and consensus in your company.

Another thing that can come up are initials, like M.B. In the case of Initials, I generally treat each as it's own word.

So, say you have this list:

Mac Alester
McBean
M.J. Liquor
Modern Interiors
Mac Phearson
Mac Flynn
McLennan
M.A. Forester

They would go in this order:

M.A. Forester
M.J. Liquor
Mac Alester
Mac Flynn
Mac Phearson
McBean
McLennan