Generative Remove is slower

System

• Lightroom Classic 15.4.1
• macOS 26.5.2
• Intel Core i5 iMac
• AMD Radeon Pro 5300 (4GB VRAM)
• 72GB RAM

Issue

Since updating to Lightroom Classic 15.4.1, Generative Remove has become extremely slow. Even a very small brush stroke (for example removing a tiny newborn skin blemish) can take over 4 minutes to complete.

The standard Remove tool works normally.

Troubleshooting completed

I have tested all of the following:

• New Lightroom catalogue.
• Existing catalogue.
• Catalogue stored on internal SSD.
• RAW files stored on external HDD.
• Camera Raw cache purged.
• Catalogue optimised.
• GPU enabled.
• GPU disabled.
• Lightroom restarted.
• Mac restarted.
• Different images.

None of these resolved the issue.

I also compared the exact same RAW file and edit on an Apple Silicon MacBook running the same Adobe account. Generative Remove completed much faster on the MacBook.

Most important finding

I installed Lightroom Classic 15.3.1 and repeated the same Generative Remove test on the same Intel iMac.

Generative Remove is significantly faster in 15.3.1 than in 15.4.1.

This strongly suggests a performance regression introduced between 15.3.1 and 15.4.1 affecting this hardware.

Additional note

I have been using Generative Remove since the beta release and it previously worked well on this computer. The slowdown has only appeared recently after updating Lightroom.

I am happy to provide sample RAW files, screen recordings and full System Info if required.