cr_sdk_########.tmp grows very large (User/AppData/Local/Temp) when batch AI Denoising

Did you solve this problem? I'm having the same issue and found this post by searching in google "cr sdk tmp" because I found that this is the file that keeps getting bigger and bigger. 

Exactly the same problem, Intel i7-12700K 32GB RAM DDR5 RTX 3060 12GB with latest drive, SSD 512GB with more that 40% free disk. When I put between 50-150 photos to noise reduction, it starts using more a more space till it stops. I can't leave my PC at night processing more than 200 photos because this problems starts. 

Side-note: 

Observe the HDD usage graph compared to the GPU usage graph:

It seems like every time before or after an image is processed, there is a large write operation happening on the HDD (it was harder to spot on the SSD, because it completes it so fast). My theory is, that this is either the input into the nerual network or the output of it and all of that is somehow aggregated into the cr_sdk_###-file. Essentially what is happening, is that Lightroom just simply forgets to clean out the completed files, for some reason.

You might want to consider redirecting Windows OS to place the temp files on a different drive.

Oh, that's interesting! I didn't realize the enhanced dng was 4 times the size, but it is indeed 😮

But I think it should not matter as the answers to your questions are as following:

1) This begs the question where are your photos stored and is there sufficient free disk space for the new images?

My photos are stored on a 6TB NAS network drive and this still has 2TB+ free, so space should not be an issue

2) This begs the question where is the folder your Catalog file with Previews and other support data files stored?

My Catalog is on a separate SSD in the system (Catalog-Size ~800MB, Folder-size with Previews ~5.33GB); the drive still has 160GB+ of space, so that should not be an issue.

3) What edits if any are you doing with the originals prior to the Denoise feature, recommendation is to do the Dnoise early in the process?

Yes, I had read that in the blog post, so this time I did the Denoise-Step as the very first thing after Import (and conversion to DNG). That said, on a prior project I actually did it after the fact (i.e. selected and edited my photos, and ran the denoise on High-ISO images prior to export). This was needed, because I could not just enhance all high-ISO photos in one go, because of the described bug or faulty behavior (but did actually work quite well!).

Just some thoughts.

The Denoise feature will create a new DNG file which will be 4 times the size of the original DNG and will be saved in the same folder of the source file. This begs the question where are your photos stored and is there sufficient free disk space for the new images?

In addition new previews will be built for the Enhanced Dnoised images and will be saved in the folder that contains your Catalog file. This begs the question where is the folder your Catalog file with Previews and other support data files stored?

What edits if any are you doing with the originals prior to the Denoise feature, recommendation is to do the Dnoise early in the process?

There is info available for the new Enhance Denoise feature in the Thread at the top of the forum announcing the update of LrC 12.4.

The drive is 256GB, perfectly reasonable for an OS-Drive in my opinion. So 68GB is around 26%. This is not a "my problem" problem, this is, I'd wager, a bug that needs fixing. No app should ever start gobbling up 60+ GB on an SSD, especially not on the OS drive (all sorts of bad things can happen if the OS drive is full) and in such an inexplicable fashion (Why does it only do it if I do more than, say,  200 photos?).

Again: The normal and expected behavior is that LR would use the memory it needs to process the files. Preferably it would use volatile memory (RAM/VRAM). If that runs out, it should use the virtual memory provided by the OS and/or use the user-defined Cache folder. In my case, LR seems to be perfectly content with the ressources at and and only works in volatile memory; at least as long as the processed photos are below ~200 (I have not determined the exact cut-off point yet)... However, go above that and LR (or the Camera Raw SDK, judging from the file-name) starts gobbling up OS-drive space like there is no tomorrow. It does NOT use any persistent storage-space (aside from the one occupied by the generated .png next to the original photo) prior to that elusive cut-off point.

This may be your problem "68GB Free on C: drive".

What is the full size of your C: Drive, you need at least 20% of free space on the drive for efficient performance?