Opening an Excel file with macro
 

I have a shared file and I will do the following:
a user with known username can open the file and change the format and a
macro should start automatically to unhide some colums.
a user with a unkwown username can read-only open the file without changing
anything in the workbook (or sheets).

a second option is to password protect a macro which will have the same
function as mentioned earlier.

Thank you in advance!