Welcome... Is it possible to protect an Excel file so that it only opens on certain computers (identified by computer name or some unique hardware identification like MAC address etc.)? Let me lay out my requirements in detail: I have an excel file "Y" created in my computer named (x1). Anyone can open this file on this computer... I want to make this file (Y) work on a certain group of computers that I specify and with my consent, for example on three other computers only, (X2,X3,X4), and it cannot be opened on others... If possible, I would like to use the protection method for some of my excel files.. Thanks in advance for any help in this regard.