Do you use CCleaner?

Hi Zenos,

Yes i do, but only the free version.

It has never previously been a problem in relation to Thunderbird.

Well, now it is. https://forum.piriform.com/index.php?showtopic=48428

Well this answers the question of what happened but doesn't really solve my problem. I am right in thinking that the information is now lost forever.

Stuart_Atkinson said

16th June 2017. The latest Thunderbird update 52.2.0 (32-bit) has deleted/remove some of my contacts, but not all of them. It has retained the contacts in my Personal Address Book and Collected Address Book, however i had created Several other address books and it is these that are no longer appearing. I know the data will still be on my hard drive, but how do i get it back into Thunderbird.

User-defined address books are treated slightly differently from the two built-ins, Personal Address Book and Collected Addresses. These are required and will be loaded automatically if present, or new empty files generated if they are absent. User-defined address books need to be created through Thunderbird so it can register them internally; it won't just display them even if the corresponding data files already exist. The registration of these data files is done in prefs.js, which we believe is the file being damaged by CCleaner. Search for filenames with a .mab extension; your user-defined address books will look like abook1.mab and so on. If these still exist, you can re-import them using the MoreFunctionsForAddressBook add-on.

Also, the update deleted my email accounts (all 3 of them). I have to add them back in. I also had to go into my Local Folders account settings and redirect the Local directory address from C:\Users\Stuart\AppData\Roaming\Thunderbird\Profiles\byy0ftul.default\Mail\Local Folders (1) back to C:\Users\Stuart\AppData\Roaming\Thunderbird\Profiles\byy0ftul.default\Mail\Local Folders. It's almost like the update was a new install.

This is consistent with CCleaner damaging the prefs.js file. This file tells Thunderbird about your accounts. Remove this data and Thunderbird starts over again. Since it is using the same profile, it comes up with exactly the same Local Folders name and has generated a new version, that is, the one with the (1) suffix to its name. So it has deliberately chosen not to overwrite existing data. Under these circumstances, pointing the account to the pre-existing Local Directory was exactly the right thing to do.

Thanks Zenos,

Contacts restored using the add-on listed above.

Is there a similar add-on to restore the calendar/event/task information.

In the folder C:\Users\Me\AppData\Roaming\Thunderbird\Profiles\??????.default\calendar-data there is a local.sqlite file that is 1056kb. I am assuming that this is my calendar data.

I just can't find a way to add it back in.