One of our customers sent me two Excel XLA add-ins. When I tried to open that file in the VBA Editor — the "Project is locked" message appeared. Add-in has been already unlocked by our VBA password recovery tool. According to Microsoft article this message may appear in two cases: when the macro is protected by password or when it is digitally signed. I analysed the macro password record and found that the password is empty. MS Excel also showed me that macro have no any digital signatures. Then I looked into protection record with more attention and for example found that:

Time is money, difficult to contradict this fact. And another proven fact is that you lose something exactly when something turns out to be absolutely necessary. Once you lost a password to your Word document or presentation that you were going to give in an hour, or Excel report which was supposed to be sent to your manager yesterday… you will count seconds before you get back your files. (more…)