Import more data from a Thunderbird account

I’ve just installed eM Client v9. On startup it asked if I wanted to import existing data - I have Eudora OSE which eM Client recognised as Thunderbird. I was unsure about whether the import would work, so I selected 1 (of about 40) folders, as a test. That seems fine, but now I cannot import the other folders. eM Client does not offer the option any more, even when I go to Import… on the menu.

I have tried uninstalling the client and reinstalling, but the same thing happens even after reinstall - it doesn’t show anything at all to import from Thunderbird.

Can you suggest how I can proceed? I’m completely stuck.