I just removed Android from my Teclast X98 Air II (32 GB), freeing up 10 GB for Windows. I have Windows 10 installed and using the Disk Management Tool I basically deleted all the partitions of type “RAW” (NOT the ones without a type or the NTFS Windows partition). Then I created a D: drive with all freed up space. Unfortunately you cannot extend the C: drive with the additional storage (you would have to reinstall Windows for that), but I simply moved app installation and paging memory to the D: drive, freeing up nearly 4 GB on my C: drive.