I moved my game and DLC from my HDD to my M2.

Clean install of RS14 (set to previous patch version so CDLC will work), set CDL path in GUI, refreshed app ID in GUI, redownloaded the D3DX9 from CustomsForge, and restarted my PC.

Now when I try to play any CDLC, I can pick the song in my library, but then it just doesn't load.
Screenshot is what happens.

Looking for any ideas, Thanks.

Couple different possibilities.

The screenshot that you provided is quite often a Rocksmith version vs .dll version mismatch.

Unclear on your post if you are using the HDD and M2 at same time, Steam on HDD, Rocksmith on M2 or are both now on the M2

Did you check in your new installation that the D3DX9_42.dll was injected into the Rocksmith 2014 folder where the .exe is / did you remove the old installation of Rocksmith from your HDD if you are still using that HDD

Are you using the previous / beta version or current version of Rocksmith. the new enabler is for the current version of Remastered and Learn and Play, not the Beta.

1 hour ago, TPxRedBeard said:

(set to previous patch version so CDLC will work),

You will need the D3DX9_42.dll for the Beta if this is what you are saying by this, and by downloading the D3DX9 from CustomsForge meaning you downloaded the current enabler (find the old .dll you were using or just update to the current version of rocksmith)

If you are using 2 different drives, one for Steam, one for Libraries, I would suggest if possible having Steam and Rocksmith on the same drive. I am not saying it won't work, just my experience is that with CDLC, enabler, etc it just does work better if all on the same drive.