Grab the window by the border and move it out of the way. BTW, have you installed the latest service pack?

My guess is that a previous conversion failed, and the data was not properly restored by deleting some of the 9.0A files. Now the conversion is complaining that those files are in the directory and that they shouldn't be.

Come to the webinar anyway - you don't need Ledger 9.0A running to learn something new.