After installing the Citrix Receiver for Mac, there will be a minimized icon running in the upper-right corner.
Right-click and choose Preferences.
Preferences will open a new window, and in the middle of that window, there is a File Access button that you will need to press.
Change the option to Read and Write, then close the window.
Log in and launch your copy of Design Manager.
When exporting a report or uploading a photo, you will see a screen like the one below to browse your local computer:
You should be expanding the Computer, Local Disk (C: on YourComputerName) option
Use the left-hand pane to expand the file tree to the desired folder, example: C:\Users\YourUsername\Desktop folder.
Double-click on the folder you want to browse to.
You can then browse your desktop, documents, downloads to locate photos or set a path to export files.
It is highly recommended to set most used folders as Favorites:
Double-click on the desired folder, then right-click the Favorites Icon, choose Add current location to Favorites
You now will have read/write access to your local hard drive, and a favorite set to your desktop or other locations. This should streamline browsing to your most used folders, and make those resources easier to find for ongoing use, without getting the access denied message. If at any point in the future you receive a popup to allow access, choose Read and Write and check to not be asked again.