Our server D drive disk space is running out soon and there is an unallocated 
disk space available, so could I create an extended partition on this 
unallocated disk space and Do Not assign any drive letter, so as to merge it 
with the existing D drive to become a larger partition?

Wilson wrote:

> Our server D drive disk space is running out soon [...]


Your question appears to be off-topic in this newsgroup...please find a 
newsgroup that pertains to the administration and use of Windows.  You 
might even be able to find one specific to configuring disk drives.

This newsgroup is for .NET Framework programming questions, and nothing 
about your post appears to be on-topic here.

Pete