Sorry to hear you are having problems with this.
Is Drawboard PDF the default program for that PDF, that you are trying to open?
Also when you say you cannot create a new PDF, what is your workflow? Please write to us at email@example.com and we can look to help you out.
Drawboard Product SpecialistJay commented
Just downloaded the app from MS App Store.
Same problem for me.
Pin Folder doesn't work (nothing happens when selected).
Open PDF via File Explorer doesn't work (nothing happens when selected).
Please tell me how to resolve this.
Also, I do not appreciate keeping some features only available on Pro (requires monthly subscription) when I thought I paid for full version.
So far, I'm not impressed.