Access to the path "Power-user\Extensions" is denied

Shortly after installation, it can happen on some computers that the following notification appears, stating "Access to the path 'Power-user\Extension' is denied":

This error means that the user of the computer is denied access to the file C:\Users\<UserName>\Documents\Power-user\Extensions, which is the default location for saving the content of the Library.

If this error happens, the easiest solution is to change the default location for saving the content of the Library. To do that, click the "Settings" button (the blue cog located at the very left of the ribbon), edit the path below "Save Power-user libraries in" and save your changes.