If BirdieSync add-on is supposed to be compatible with the version of Thunderbird/Sunbird but doesn't load properly, there might be a problem with Thunderbird/Sunbird extension manager cache (this can happen if BirdieSync was not uninstalled before installing the new version). This problem can prevent BirdieSync sub-menu to be properly displayed in Tools menu or display an old incorrect version number in Thunderbird/Sunbird add-on list. More rarely, it can also make Thunderbird/Sunbird crash.

If you use Thunderbird 1.5 - 3.1 and Sunbird 0.3 - 1.0b1:

Before any operation, do backup your Thunderbird/Sunbird profile:

XP: C:\Documents and Settings\[users]\Application Data\Thunderbird\Profiles\
Vista/7: C:\Users\[users]\AppData\Roaming\Thunderbird\Profiles\

XP: C:\Documents and Settings\[users]\Application Data\Mozilla\Sunbird\Profiles\
Vista: C:\Users\[users]\AppData\Roaming\Mozilla\Sunbird\Profiles\

(Application Data is a hidden folder: in explorer window, you must check the option "Show hidden files and folders")

Close Thunderbird/Sunbird.

In the profile of Thunderbird/Sunbird, after having backuped the following files, delete them:

- extensions.cache
- extensions.ini
- extensions.rdf
- compreg.dat
- xpti.dat

Relaunch Thunderbird/Sunbird.

Check if you can now access to BirdieSync options.

If you use Thunderbird 5.0+:

Before any operation, do backup your Thunderbird:

XP: C:\Documents and Settings\\Application Data\Thunderbird\Profiles\
Vista/7: C:\Users\\AppData\Roaming\Thunderbird\Profiles\

(Application Data is a hidden folder: in explorer window, you must check the option "Show hidden files and folders")

Close Thunderbird.

In the profile of Thunderbird, after having backuped the following file, delete it:

- extensions.sqlite

Then restart Thunderbird.

Check if you can now access to BirdieSync options.