How To Change the Drive Letter of the Windows Temporary Disk
You can change the drive letter of the temporary disk if you need to use the D drive for another purpose. Most likely you'd do this to support an application or service that uses the D drive as a permanent storage location.
Before you begin, make sure you’ve got the following:
Change the drive letter
Log in to the virtual machine.
Move pagefile.sys from the D drive to another drive.
Restart the virtual machine.
Log in again and change the drive letter from D to E.
From the Azure Management Portal, attach an existing data disk or an empty data disk.
Log in to the virtual machine again, initialize the disk, and assign D as the drive letter for the disk you just attached.
Verify that E is mapped to the Temporary Storage disk.
Move pagefile.sys from the other drive to the E drive.
How to Log on to a Virtual Machine Running Windows Server
How to Detach a Data Disk from a Virtual Machine
What is a Storage Account?