P: Bring back the ability of Enhance to run in the background. (LrC)

Their whole argument boils down to "we can't risk the user doing x, y, or z while Denoise is running", so yeah, it is pretty much as simple as graying out those options while Denoise is running. It's not equivalent at all to completely removing features that some users wouldn't miss. At the end of the day, there was a small incompatibility, and rather than deal with it individually, they slapped a lazy nuclear option on top as a "good enough" fix that isn't actually good or enough. 

@johnrellis wow it's a real mess, I'm glad someone knows where we're up to!

@Generous_view0D45 I agree with your sentiment, but also understand it's a little more complex than greying something out. The problem is adobe are trying to cater to so many people with so many different use cases that many are probably unaware (including the developers) in ways others use and rely on different parts of the software. 

Personally, they could drop the map, book, slideshow, print windows from the app and I wouldn't miss them at all but others would be up in arms. It's just frustrating that there's no space for a meaningful conversation to be had about it

"adobe listened on the catalog size issue and are moving to extra xmp/acr files for large AI meta data away from the catalog again."

It's more complicated than that. In LR 15, denoise and other computed AI data is still stored in the catalog folder.

In LR 14.5, denoise data was stored in the .lrcat-data file in the catalog folder. If you did Metadata > Save Metadata To File (manually or automatically), the denoise data was also stored in .xmp sidecars and in the .lrcat file (the catalog SQL database).  Adobe acknowledged that the extra copying to the .lrcat file was a bug.

In LR 14.5, denoise data is still stored in the .lrcat-data file in the catalog folder. But when you do Save Metadata to File (manually or automatically), the denoise data is also written to the .acr sidecars. It is no longer written to .xmp sidecars or copied into the .lrcat file in the catalog folder.

So in both LR 14.5 and 15.0, the primary location of the denoise data is in the catalog folder. But if you do Save Metadata To File (manually or automatically), then in 15.0 you get one additional copy of the denoise data in the .acr sidecars, rather than two additional copies in .xmp sidecars and the catalog folder's .lrcat file.

Wild to be here making excuses for a multi-million dollar corporation.

they would need some way of blocking the use of other ML models while it is doing denoise in the background

You mean graying out elements? Like they already do with the Denoise slider when Denoise isn't enabled? Like they already do with vignette settings when vignette isn't enabled? Or hiding elements altogether like the b&w mixer which isn't shown if using a b&w profile that isn't Adobe B&W?

@Jao vdL , Thanks for that info.

Folks. The Adobe engineers explain the issue in the pinned reply:

"Running Denoise in the background while trying to run Reflection Removal (or some other "heavy" ML model, take your pick) in the foreground is very likely to destabilize the machine, especially on Windows, which does not offer GPU/ML model memory protection. When we first introduced Denoise in early 2023, it was by far the most GPU-intensive ML model we had, but there weren't many other models that would "compete" with it. That's not true anymore."

The issue is that their use of ML really ballooned in the time since denoise was introduced and they would need some way of blocking the use of other ML models while it is doing denoise in the background and that would need a fairly large revamp of the GUI of the program. So they simply chose to just block the entire GUI instead of risking these rather bad crashes. You can argue about the decision but the reasoning is right there at the top of the page. This also indicates that we are unlikely to see a return of background denoise until the GUI gets revamped to allow some kind of blocking of certain operations which I only see happening on Lightroom Cloudy to be honest unfortunately.

@DdeGannes I agree people should, and I could live with these updates if adobe would just remove the blocking part of the process, it's totally unnecessary when the kind of photographer who need to hammer their machines typically have machines powerful enough to do so. 

I'll also note you might not appreciate the latest v15, as after some research, it looks like adobe listened on the catalog size issue and are moving to extra xmp/acr files for large AI meta data away from the catalog again.

@lukedyson , to each his own, I prefer the new Denoise process with the LrC edits stored in the Catalog and support data files. No additional DNG file created to store and manage. I use LrC in its default mode so I do not have the option " automatically write metadata to XMP " nor do Save Metadata to the file.

Users can choose the options available that best suit their own preferences.

I have already deleted thousands of DNG files created in the earlier versions of Denoise from my system. I retain my RAW originals that I revisit as needed.

@DdeGannes this only complicates the workflow, having to manage files in bridge,  camera raw and lightroom classic to achieve something that used to just work in lightroom. not to mention handling metadata changes having to overwrite one way or the other would negate being able to multi task in the first place

Not to mention the bloated catalog files with the new non DNG denoise setup. Once I've finished an album I move the raws and DNGs to my external hard drives. Now that DNG data lives in the lightroom catalog to clog up my main hard drive!

There's so many posts across the internet of people remaining on 14.3.1 because of this:

https://www.reddit.com/r/Lightroom/comments/1m89125/is_the_new_denoise_update_driving_anyone_else/