You may run into a CAD error that requires you to turn on your hidden files and folders in Windows.
Open your Start menu, and select File Explorer from the menu.
Windows 8 users: Right-click the "Start Menu" icon in the bottom left corner of your screen, and select File Explorer.
Select the View tab, and check the box for Hidden Items.
Your hidden files and folders should now be visible.
Open your Start menu, and select Computer.
Select Folder and search options from the menu that opens.
The Folder Options dialog box will open. Select the View tab.
Select the Show hidden files, folders, and drives option.
When finished, click OK. Your hidden folders are should now be visible.