I recently discovered an issue with Adobe XD that pertains to files that are saved to the local hard drive (to be clear, this is NOT an issue with files saved to the cloud). The Issue: If the ".xd" file is saved in a folder that uses the question mark character (?) in its name, then Adobe XD will report the error "The document "your-document-name.xd" could not be opened. XD cannot open files in the "folder" format." The Solution: This issue is easily resolved if you rename any "offending" folder name replacing the "?" character(s) with another "valid" character. Notes: - After I found the solution, I tested several other "special" characters in folder names, but my testing did not reveal any other characters that resulted in the error mentioned above. I certainly didn't test every "special" character, so there may be other characters that cause this issue. - It may be important to mention that I experienced this issue using Mac OS. I have not tested to see if this issue can be duplicated on a machine running the Windows OS. - It is also important to mention that the XD application only presented the error mentioned above when I attempted to open the ".xd" file from a thumbnail in the "Recent" payne of the Adobe XD "Design. Prototype. Share." window. When I double-clicked the actual file in the Finder, the file opened normally, and without issue.