Windows 10 defrags drives automatically. Check out sequoiaview great app to visualize drive storage and yes I looked for background windows asking for user input while installing Dimension Pro. There were none. Also, rapture installed fine. If there was a problem with the drive it had numerous opportunities to fail during these other installs. 
 
Briefly a window came up showing it was unpacking samples then it disappeared yet command center stayed open.
 
Both times Dimension Pro seemed to install correctly. It opened and worked fine in Cakewalk. The problem was I had to shut off command center manually in spite of its complaint that a program (It said) was still installing, after waiting two hours on both occasions.
 
I am just being more careful to create restore points after each and every install of consecutive programs.

how do I install the samples on a D drive?  My C: SSD is only 128GB.I want to install the samples on another drive

Before installing create a directory junction for the multisample folder pointing to the actual location where the samples should go. If you need help with the syntax, provide the full path to the folder on the D: drive and I can provide the command. The folder on D: must exist before creating the directory junction.

^^^ That's how I do it. All my big samples (Cakewalk instruments, Kontakt, Superior Drummer 2 and 3, Omnisphere, Keyscape, Trilian) are on one drive (E:). Kontakt and Superior Drummer make it easy to relocate, but Spectrasonics and Cakewalk don't. Junctions are the solution. They let the installer think it's happily writing to C:, and the instrument thinks it's reading samples from C:, but Windows is silently redirecting both to E:.

+1, If you are running a small C: drive, you will want to use junctions. If you establish them before the install, the installer will be none the wiser. The one specifically for DimPro is:
 
mklink /j "C:\Program Files\Cakewalk\Dimension Pro\Multisamples" "D:\Cakewalk Content\Dimension Pro\Multisamples"
 
[I put all Cakewalk samples the the Cakewalk Content directory.] As scook mentioned, the target (D:\Cakewalk Content\Dimension Pro\Multisamples - or whatever you choose to use) must exist before the junction is made, and the junction point must not exist (C:\Program Files\Cakewalk\Dimension Pro\Multisamples, which is also the default target of the DimPro install).
 
I wrote this post a few weeks ago about how to manage disk space on the C: drive, with some junction examples of primary heavy hitters (I junction everything to the D: drive).

Just to add to this thread in regards to the installer hanging - had this last week on a fresh win10 install. DimPro opens afterwards but I can reproduce it crashing by just auditioning patches with large amount of keystrokes/midi notes. I have read about certain patches being the culprit but havent been able to verify as i reproduced the crashing by using the same patch each time so IT could be the problem.