“I had backed up my Thunderbird address book a few years ago. However, when I am now trying to view MAB file, it displays an error that MAB file cannot be opened. I need to view the contacts immediately. Is there any scope of opening such backup file?”
Yes, MAB viewer Freeware can be used to open and read Thunderbird address book backup file. You just need to open MAB file in the application, it generates a listed view of the embedded contacts.