Good day,

Please make sure you are logged in as a Windows Administrator. If the error persists, please run a Reset to Clear the Registration and re-register Pastel.

The reset utility is located on C:\Pastel17/18/19
Locate the Reset19.exe. (the example below is for v19)
Double click on Reset19.exe
Select the options -
Clear Registry and Clear Registration and Close
Go back to the Pastel Program and re-register
Complete the registration
Close Pastel and re-open it again

Please refer to the screenshot below;

Kind Regards,