teresawill

I have same trouble now and thanks to all the points people shared. It really helps a lot.

It is a pretty simple problem. You cannot extend your C drive because the built-in disk management only works when the unallocated space is adjacent to C drive. Unluckily, the disk management has no function named "move partition". The only way you can extend your C drive, with Windows disk management, is to delete your D drive. However, you may lose data, too. So, you'd better use a third party partition software to complete this case, just like I did before. BTW, I used AOMEI Partition Assistant before.