Mailbird is able to fully import from Thunderbird, Outlook and Windows Live Mail.
Import instructions are provided in this other article, however, some customers may encounter a problem whereby Mailbird cannot find the existing profile to import.
Mailbird will look for your profile for import in the following folder: C:\Users\[username]\AppData\Local\[Microsoft or Thunderbird]\ - however, sometimes this location can be changed, and the profile moved.
In order to rectify this, you will need to find where your profile folder has been moved to. If you previously moved it elsewhere, please move it back to the default location (i.e. C:\Users\[username]\AppData\Local\[Microsoft or Thunderbird]\) and then try to import it once again.
Hopefully you have found this article useful, but if you still require assistance with this problem, please do not hesitate to contact our Customer Happiness Team by clicking here.