Opening a Detail view (until I can edit, move sliders, etc..) can take 30 seconds

Question

I have a problem. Lightroom (not Classic) runs incredibly slow on my MBP with M4 and 16GB ram.
How slow?

Opening a Detail view (until I can edit, move sliders, etc..) can take 30 seconds.

After opening a folder, I can't change star rating for 20 - 30s.

Copying Edit Settings can take around 30 seconds (1 photo).

AI edits like Denoise take between 1 and 2 minutes per photo.

Exporting 10 photos take 10 minutes.

No even mentioning minor hiccups like lags when moving sliders etc. All in all, it's unuseable.
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Few more details:
- All photos are stored locally on the system SSD.
- More than 150 GB free on the SSD
- All photos are 61MP uncompressed RAW, with ~80 photos per folder.
- More edited photos in the folder result in even slower operation.
- LR cache allowed to use max. size
- The app is updated.
- MacOS is updated.
- GPU setting in LR: Auto (but same issue when on / off)________System info:
Lightroom version: 9.0 arm64 [ 20251017-1944-414afc8 ] (Oct 17 2025)NGL Version: 1.42.0.5WF Version: 8.0 58cbd19VF Version: 1.0.164HIL Version: 40501CAI Version: c2pa-c/0.6.0 c2pa-rs/0.46.0PH Version: 5.2.3Adobe GSDK Version: 1.4.0.42CR Version: 29.5.0.202509162212_6e7a997
Operating system: macOSOS Version: macOS 26.0.1 (25A362)Application architecture: arm64Computer model: Mac16,1 / Apple M4Logical processor count: 10Real memory available to Lightroom: 16.384,0 MBReal memory used by Lightroom: 2.470,0 MB (15,0%)Peak memory used by Lightroom: 4.164,0 MBMemory cache size: 3.472,8 MB
Internal Camera Raw version: 18.0 [ 2389 ]Maximum thread count used by Camera Raw: 6Camera Raw SIMD optimization: NeonCamera Raw virtual memory: 1284MB / 6144MB (20%)
Display: 3024x1964
Graphics Processor Info: Metal: Apple M4Graphics Processor Detail: loaded: Yes, supported: Yes, compute: Yes, init: I4_GPU4, hard: success, soft: success, al: Yes, dl: NoOS Media Capability: true
_____Is there a fix for this? Photoshop runs without issues, but LR is a pain..

Noel Orridge · Answer

Hi there! I'm sorry to hear that you're having trouble with Lightroom. Could you please let me know if this issue has just started or if it's been ongoing for a while? In the meantime, here are some steps you can try that might help improve the situation.

1) Clear Camera RAW cache: In Lightroom's Preferences > Cache and click on Clear Cache.

2) Try setting your GPU performance mode to High: In Lightroom's Preferences > Performance > Select 'High Performance' for Graphics Performance.

3) Delete the AI Model Cache: Go to Finder, User > (Command + Alt) to find the hidden Library > Application Support > Adobe > CameraRaw > ModelZoo. Delete the entire contents of the ModelZoo folder. This should help with Denoise performance.

4) Delete the Camera Raw GPU config file: User > (Command + Alt) to find the hidden Library > Application Support > Adobe > CameraRaw > GPU > Adobe Lightroom > delete file Camera Raw GPU Config.text. Perform steps 3 and 4 in succession, then restart Lightroom.

5) Try resetting your preferences: When starting Lightroom, hold down the Option key and the Shift key. Lightroom will start completely reset to the default after you confirm that you want to reset preferences.

Let us know how it goes!

Please use @ before mentioning my username so that I can be notified ASAP.

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