Everyone that works with DAZ Studio for any length of time quickly runs out of disk space.
Moving your content library to a bigger drive is a routine exercise for Studio users and artists and the process is actually quite simple.
The first step is to actually move your content and free up space on the current hard drive.
The second step is to point DAZ Studio to the new location.
This is usually a routine and painless process and if all goes well typically results in no downtime or loss of Smart Content but even if that were to happen, all’s not lost and you certainly won’t need to re-download your products again from DAZ3D.
Step 1- Move your content
This assumes your new drive is already attached to your computer either internally or externally, has been formatted, and is visible and available to Windows. If not, do that now before proceeding.
First, find out where your current content library is stored by opening up Studio and going to the Content Library tab then selecting the pancake menu on the right side of the pane and selecting the Content Directory Manager.
Make note of the entries for DAZ Studio Formats and Poser Formats. There may be one or more rows listed under each category.
Select one of the rows, then right-click on “Edit Base Directory”. This will open up an Explorer window to that directory.
Copy the path in the address bar at the top of the Explorer Window by clicking in the address bar area and copying the path that is displayed.
Open a Notepad window and paste this path into it.
Delete everything after “…\My DAZ 3D Library” in your Notepad window.
So for example, if the path you have in Notepad is:
C:\Users\John\Documents\My DAZ 3D Library\Environments\
You would delete “Environments” leaving only: C:\Users\John\Documents\My DAZ 3D Library\.
You can close the Content Library Manager window and shut down DAZ Studio. It’s a good idea for DAZ Studio to not be running while you’re copying your data.
Next, open a Windows Command prompt on your Computer. You can do this by type Win+R on your Keyboard and typing cmd+Enter or navigating to Start/ Windows → Windows System → Command Prompt
For the sake of this tutorial I’m going to assume your new drive is drive E:\ but if your new drive is a different drive letter than use that instead. 
You’re probably familiar with moving files around in Windows Explorer, but Explorer is quite slow when moving lots and lots of files. There is a much faster and better way and it’s called robocopy and it comes with every version of Windows.
robocopy has a lot of options, but for our purposes we’re only interested in one of them. “/E” for “Copy all subdirectories, even empty ones.”
The next argument you give robocopy is the path for your source material to copy (this is what you copied into that Notepad window up above), and specify the destination.
I recommend you move your “My DAZ 3D Library” folder to the root of your new drive. It will make finding it in the future much easier!
So with all this at hand we need to tell Windows to begin copying.
Type robocopy /E " into the command prompt window, leaving a space and a double quotation-mark after the “/E”. Don’t hit Enter just yet.
Next. copy that path that you have in that Notepad window. For this example it was C:\Users\John\Documents\My DAZ 3D Library remember? And Paste it into your Command Prompt window by pressing the Right Mouse Button on your mouse/ trackpad.
Now add a closing double quotation-mark to the end of the path.
Don’t press Enter just yet!
So let’s look at your Command Prompt window. It should now look like:
robocopy /E "C:\Users\John\Documents\My DAZ 3D Library"
Now we need to tell robocopy where to copy the files in C:\Users\John\Documents\My DAZ 3D Library to.
Add a space and another quote. And if you recall for this example our new hard drive is drive E:. And we want robocopy to move our My DAZ 3D Library to the root of E: so let’s tell robocopy to place our copied files in "E:\My DAZ 3D Library".
So our command prompt should now look like:
robocopy /E "C:\Users\John\Documents\My DAZ 3D Library" "E:\My DAZ 3D Library"
If your’s looks like the above (adjusting for your own drive letters and path) then go ahead and press Enter.
Robocopy will now begin its magic!
Pay attention to your Command Prompt window. Robocopy will tell you what it’s doing every step of the way.
If you even need to shut your computer down or if your power goes off, you can always have robocopy pick up where it left off by entering the same command again into another command prompt window.
Step 2 - Telling DAZ Studio where your new files are
You point DAZ Studio to your new file location by going back into Content Directory Manager in the pancake menu of the Content Library Tab and adding a new entry for your new My DAZ 3D Library location on Drive E: (or wherever). Whenever you are satisfied that everything is where you want it in your new location you can delete the old entries out fo the Content Directory Manager and delete your original My DAZ 3D Library location in C:\Users\John\Documents\My DAZ 3D Library to free up your disk space.
Hope this is helpful.