Has anyone done this with a Bluesound Vault?

Haven’t done it yet, but will be at some point (just 10% into ripping my CD’s ... isn’t this a function of re-indexing the library?

Yes I think you are correct, that is the end step.

I am at the point now where my files are ready and I will start moving albums over from my HDD to the Vault HDD, most likely in small batches of 10 at a time. I can report back here if the Vault has any problems reading and playing the files. Crossed fingers.
I have about 500 gb of albums (uncompressed AIFF files) which should take about 1/4 the space of the 2tb drive in the Vault.

I assume you know this already, but in case you don’t...the files don’t need to reside on the HD of the Vault in order to be played.  As long as your computer and the Vault are on the same network, the Network Player function of the Vault will recognize and play them.  No need to use up the Hard Drive of the Vault.
  If the goal is to clear the HD of the computer, you can transfer the files to a separate HD and the Vaults will still play them

Mahler.. good to know. Thanks. I have been playing these files from a MyCloud HDD, just wanted to keep all files in one place. That's kinda why I bought the Vault but your point is good information.... I am probably slightly OCD with this preference. haha

I get it...however, the BlueOS will treat all your files as if they all are in 1 place.  Or, if you prefer, you can still look them up by which HD (Library) they reside on.
in theory, you can be playing files from an infinite number of HDs, and not be limited to 2 TB storage.
  I am not sure but I think the newest version of the OS will also treat files from streaming services ( I use Qobuz) as if they reside on the Vault as well.  The last time I used it I notice some of my Qobuz files were in there.  Roon has offered this for a while and it is one of it’s big selling features, so I am guessing that Bluesound is trying to do the same.
  I had moved on from Bluesound to Melco in my two channel system but moved the Vault2 to aHT system.  I just enabled the Vault2 to play files from the Melco just a few days ago and I haven’t really played around with it much

I’m about to go through a similar process with the vault and am wondering if a cache of music on my PC hard drive ripped using DB power amp can *simply* be added to the vault with metadata of course. Anyone try this?

Yes, I have done that. I felt it’s better with the files inside vault. You just need to re-index to get all the artwork.

Well I have successfully moved about 40 files (Albums) from a My Cloud hard drive to the Bluesound Vault using my Macbook Pro. The Vault has a rips section and a music section to the HDD. The files move to the music section. I followed this guide on my mac to get the IP address of the Vault.
https://support1.bluesound.com/hc/en-us/articles/200387457-Accessing-the-Bluesound-Vault-s-Internal-...
So far, so good. But I have not played the music yet. That will be next step.... stay tuned if interested.