Have you ever met the situation that you cannot extend volume of C Drive on Windows Server 2008 R2? I met before, and solved after learned the limitations of Disk Management in Server Manager.
Limitations of disk management to extend volume:
1. Extend Volume will be active when there's continuous unallocated space followed the volume you want to extend.
2. File system must be NTFS
Low disk space problem must be solved in the original system before you install Windows Server 2008. If you were using Server 2003, then there's no extend volume in disk management, the only way is to repartitioning if you don't use other partition managers to distribute space. That's not the solution to solve not enough space problems.
In daily use, we recommend not to make you temporary folders full, clean this folder regularly to free up much space for later use. Please don't set default download path to this Volume either, but if you already done that and been there, Partition Extender is the best choice to manage disk space without repartitioning or reinstalling.
There're mainly two ways to make enough space for temporary files produced by Server system. The first is to clean up other files and free up space for new temporary files after copying the original files; the second one is to extend partition with temporary folders in Disk Management or other partition magic server like Partition Extender.
Or Steps to extend volume in Partition Extender without data loss in Windows 2008