Main image View hangs up to 10s when switching photos in develop, rest of the UI stays responsive.

[Wolfgang Lienbacher]

I'm having issues with the speed of the develop module. It completely disrupts my workflow and significantly slows down my pace. When I'm finished selecting my images and I quickly want to adjust my images in the develop view, most images display instantly as expected. But sometimes the all of the UI changes, except the main image view. I can even do adjustments in the dev panel (I use a streamdeck via plugin to do this) and the commands arrive in the develop pane, but the image in the main view is still the old image, and it does not update. This can take up to 10s. 

All this is happening on a Macbook Pro M4 Max with 64GB RAM und 2TB SSD. The images are RAWs from a Sony Alpha 1. From a pure technical point of view, there is really no reason why it could take this long to load 55MB of RAW data from SSD into any kind of other Memory on this type of hardware.  

I would love to find out which piece of software is blocking the main image from displaying for such an incredibly long time. I am also unable to reproduce the problem. I thought deleting the previews from the catalog entirely via finder would give some remedy, but actually it's not. It is a problem that is occurring *every* single time I edit a job, but I cannot reliably perform a routine that would trigger the problem to occur. It's a completly random thing to happen every 1-10 photos, but only while editing images. If I just scroll through the images in develop, it seems it does not happen. But If I do copy and paste commands and adjust a few sliders it happens routinely and it's honestly driving me crazy. 

Anyone else experiencing this kind of behaviour in the recent versions? I feel like it hasn't been this severe in the past. 

[dj_paige]

What software are you using? What version NUMBER? (We need the version NUMBER and not words like "latest" or "up-to-date") What version NUMBER of MacOS?

[Wolfgang Lienbacher]

Mac OS 26.1 and LR 15.0. 

It has however not been specific to these versions, it's been happening in the past few versions as well, I only had the romantic idea that issues like these would resolve themselves at some point in thime, but I've come to the conclusion that this is indeed just a romatic idea. 

[DdeGannes]

@Wolfgang Lienbacher , you stated in your original post " I can even do adjustments in the dev panel (I use a streamdeck via plugin to do this) and the commands arrive in the develop pane, but the image in the main view is still the old image, and it does not update. This can take up to 10s."

There have been significant changes to LrC in the past two years, have been getting updates from the developers of the Plug-in you are using.

[Wolfgang Lienbacher]

I am 99.9% sure the problem is not in any way related to the plugin. All the plugin does is make calls to LrDevelopController,  namely increment(), decrement() and setValue(). As far as I am aware, this is nothing that has seen any kind of significant changes that would require an update of a plugin.

In any way, I used it as a way to describe the symptom. All keyboard shortcuts work as well while I wait for the main image View to update the image. I really only wanted to outline that the Lightroom UI seems to be responsive. 

[Wolfgang Lienbacher]

Been thinking about this again, even if it was the plugin, all the plugin does is open a socket, wait for commands and send those commands. It also reads all values and sends those via the socket for the values to be reflected in the displays of the streamdeck. 

So, let's assume it was the plugin taking 10 seconds to read the values of all sliders, and send them via the socket, this would mean the lightroom plugin sdk would block the develop image view from rendering, but at the same time allow the plugin to receive and control the develop sliders with no issue. I think it's save to assume that if this was true, this would qualify as an architectural bug in the lightroom architecture that should be fixed. 

I'll have a look at the stream deck next time the bug occurs during editing, if the the slider values update when the images are switched but the view is not rendered I can rule out this issue, if it is not I'll investigate further. 

Additionally: I assume you are not experiencing this kind of problem at all?

[DdeGannes]

I do not use that Plug in.

However there is a new update to LrC version 15.0.1 that has several critical bug fixes.

• Lightroom Classic 15.0.1 is available for download.
•  

[johnrellis]

It's easy to rule out issues with the plugin: In File > Plug-in Manager, select the plugin and click Disable. Restart LR. If the problem still occurs, you know it's not the plugin.

[WillCheung]

The same problem

[Ian Lyons]

@WillCheung 

You already have a thread describing your issue and it has received feedback. Adding your 'me to' to this thread is neither helpful nor required. If you have something meaningful to add or somthing that hasn't already be mentioned in your other thread, then please update that thread.

Existing thread by @WillCheung 

https://community.adobe.com/t5/lightroom-classic-discussions/performance-issue-in-lightroom-classic-...

[Oliver Andrews]

Are you saving XMP files? If so try pausing that whilst you're editing (click on the identity plate top left and it's in the drop down menu).

[Wolfgang Lienbacher]

I indeed save XMP files. Is there a known issue with this? I'm having trouble aligning saving a 4kb xml file with freezes rendering a develop view, but indeed I remember LR occasionally bragging about still being busy writing xml files, which always made me wonder how such a simple task could possibly take so long on modern hardware ...

I'll give that a try once I manage to rule out the plugin. 

[DdeGannes]

@Wolfgang Lienbacher , you need to be aware the Default option of LrC is not to write XMP to the file, when you are working with LrC the application is reading and writing to the Catalog file. LrC can function without XMP files.

When you import images into LrC and there is XMP data available the data will be reading,  LrC does not "Automatically Read info from XMP files, this requires a manual input from the user.

There is an Option in the Catalog settings to Automatically Write Metadata to XMP, however this is not a primary function so info is first written to the Catalog. The XMP data is necessary to share info to Bridge/ Camera Raw of other applications.

When you have the option selected performance will be affected particularly if you are using edits using AI functions like Denoise etc.

You can pause the Auto Write to XMP when carrying out these functions and unpause it again when you have finished your editing.

[Wolfgang Lienbacher]

Thank you @DdeGannes for your reply. I am a Lightroom User since 1.0 and am well aware of what xmp data is used for and what not. The decision to turn XMP on was conciously made quite a few years ago. 

We are using Computers with >10 Cores and Memory Bandwidth of >500GB/s, and use SSDs capable of writing multiple Gigabytes per second. If reading and writing text files of a few kilobytes is causing severe performance issues, then this is a software problem that can and should be addressed. 

[DdeGannes]

@Wolfgang Lienbacher , no problem and I respect your choice to write metadata to the file.

The reality is that there will be an effect on performance.

[Oliver Andrews]

As of v14.4 LrC now batches up XMP changes and writes out the files every 10 seconds, instead of writing all the time in the background. Since that change I've had the same freezing of the main image in the development module that you describe, and pausing XMP writing whilst editing solves it. I'm assuming before that change it used to freeze more frequently but for less time, and I just didn't notice it as much.

[Wolfgang Lienbacher]

Thank you for sharing your experience and insights Oliver! That's a very intersting change that sure makes sense. However, I'm still trying to wrap my head around Lightroom being able to generatp previews of thousands of images within minutes, but still freezes for seconds when writing a few kilobytes of xml data to disk. If this is true I'd say it's very safe to say that's a serious bug. 

[Wolfgang Lienbacher · Accepted solution]

I am finally able to confirm a solution. It took me quite some testing. It turns out part of the problem was XMP writing, pausing this gave a noticable boost in responsibility, but the main issue was in part the streamdeck plugin, but after all not the plugin itself, but the Streamdeck version from version 7 on. Version 6.9.1 works perfectly fine, but with version 7 the plugin causes severe lags. I also noticed having one dial on my Streamdeck + on the arrow key would cause seriously severe lags while scrolling through images. Downgrading to V6 has brought Lightroom back to speed in a number of ways. It was quite a surprising find! 

I have relayed the Problem to Elgato, as of now there is no fix yet. 

[johnrellis]

@Wolfgang Lienbacher, thanks for the update -- that will help others.  There are lots of reports of sluggishness in LR 15, and it's become clear that there are several different causes.