This error occurs when BootCaT is unable to create a folder for the project, this usually happens because of incorrectly set file or folder permissions (maybe you logged in with a different username than usual).
A solution for this is to change the folder where BootCaT saves your corpora (the default is your “Documents” folder in Windows or your “Home” folder in MacOS).
To change the default folder follow these steps:
'C:\bootcat
'):
That's it, now BootCaT should work normally.