Pls try to use another SD card with software installed. if the card still cannot be recognised, it might be hardware issue of sd card slot in the DS708.

 hello, Im having the same issue with my maxisys pro. It keeps asking me to format /mount the card but it just will not recognize it. could it be a formatting issue? should it be fat32 maybe?

 if your card worked at one point and is now saying that, then you must insert the card into your computer, then go to the command prompt and type: chkdsk /x /f (your drive letter). for example my drive letter was g:/ so i typed in chkdsk /x /f g:/ and it will verify integrity of the card

 I found the solution to my issue as well. My card was in exfat format and needed to be reformatted in fat32. Using aomei partition assistant i was able to reformat in fat32. now all is well and my card is recognized :)