Hello there,
I do think u r creating this partition as we do shrink volume, that is why it is showing like this. so that means you are trying to create this partition in C drive. I can make this partition as a usable partition but in future if something wrong happen to your c drive and that time u would like to get data from ur drive u r going to create, but in that time u can not get this data, coz this is the partition we can create inside the C drive, otherwise take backup of desktop and fromat your system and create partition from there. if u do not want format ur system leave massage again I ll tell u this trick, right now I am suggesting u to do not create partition from here coz u have only partition that is C.