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Rebuild Thunderbird Address Book – Recover MAB Files

Mozilla Thunderbird email application comprises of two contact folders within it i.e., abook.mab and history.mab. The extension of address book file in this email client is .mab. Well, consider the following scenario posted by the Thunderbird user on Rebuild Thunderbird Address Book error:

“Due to some unknown reasons, my Thunderbird address book got deleted and I received an error message i.e., ‘Unable to load address book file abook.mab. It can only be in read-only or locked by any other application. Try again’. First of all, I am unable to locate this MAB file and another thing now I am feeling helpless because it seems difficult for me to come out from this situation. Please, someone, help me out!”

The solution for getting rid of this situation is to rebuild the Thunderbird address book because, by default, the contact items are stored in profile folders. In general, there are following three ways to resolve this problem:

Tip: There is a recommendation for email client users that they should regularly take backup of their profile data, including all mail folders, contacts, calendars, etc. It is so because the most appropriate and relevant approach during disaster recovery is to restore those backup files.

Apart from this, other solutions are also available, which are described in this blog. First of all, we are going to discuss the most common reasons that are causing corruption in Thunderbird address book and then proceed further with ways to resolve the problem.

Possible Situations Causing Corruption in MAB File

Following are all conditions, which makes MAB file corrupt and hence, becomes a reason to rebuild Thunderbird address book:

Rebuild Thunderbird Address Book In Different Ways

Solution #1: Recover abook.mab Files From A Damaged Thunderbird Profile

This method is applicable for those users who are regularly taking backup of their Thunderbird profile. Go through following set of instructions to perform the same:

Note: It is mandatory to have same name of the old profile in new one

Solution #2: Repair Corrupt Thunderbird Address Book And Extract Data From It

Whenever there is corruption in a MAB file then, such file gets named with abook.mab.bak. Fix the problem by rebuild Thunderbird address book, follow below set of instructions:

Windows XP: C:\document and settings\*user name*\application data\Thunderbird\profiles\*random string.profilename*

Windows 7, 8, 8.1, 10: C:\Users\admin\AppData\Roaming\Thunderbird\Profiles\f6gm8qf5.default

Note: First of all you need to set Windows settings in such a way that hidden folders/files are visible to end users

Solution #3: Replace Address Book From Its Parent Profile To Another One

Follow below-mentioned steps to perform the same:

Finally, all your contacts will be loaded in Thunderbird and then you can access files without any problem.


In order to recover Thunderbird address book, we are just working with Thunderbird email application. Talking about any relevant approach then, all are foolproof and work successfully to rebuild Thunderbird address book. After implementing these steps, readers are requested to put a comment below sharing their experiences with us after using the described solutions.