The Design Master customization folders need to be read-write in order for our software to work. The files in the folder can be read-only if you want to limit who can make changes to them.
This requirement is necessary because the Jet database driver that we use needs to be able to create a temporary lock file in the folder when it opens the database. If you do not have permission to write to the folder, this will fail.
This applies to the HVAC Customization folder, Electrical Customization folder, and Plumbing Customization folder.