Mounting drive to NTFS folder does not work

I am having issues with getting my card reader to mount in NTFS folders. I recently upgraded from Windows 8.1 to Windows 10 and had this issue. I then did a clean install and the issue continues.

Basically, I go to disk management and add a driver letter or path to the SD card slot in the card reader. I then point that to a folder on my d drive: "d:\_card_reader\SD Card". After this I delete the drive letter associated with the SD card slot "H:".

When I go to navigate to the SD card slot I get the following error: "D:\_card_reader\SD Card\PRIVATE is not accessible. The system cannot move the file to a different disk drive."

I have been doing this since Windows 7 with no issues, but cannot get it to work with windows 10. I can access the SD card itself, but not any folders. The PRIVATE folder for example contains the video files from my camera. I cannot let the card reader take up drive letters because I work with video and I use a lot of hard drives. I may not have 26 drives at the same time, however I like to work between different workstations and I assign drive letters to drives. If I do not assign drive letters, then my software will try to search for video files. Something like "I:\08_17\C0001.mp4 cannot be found". Then I have to scan the drive again and sometimes manually find the clips. When working with 400+ clips per project and deadlines, this is wasted time.

Also, this problem is NOT only for the card reader. I cannot mount my backup drives like this either. I have 4 backup drives in "d:\_3TB BUPs" and all of them give the same errors. For now, I have to use drive letters, or use my Laptop with Windows 7.

Are there any solutions to this? Thank you in advance.