Thanks for your patience, @matteo_8161, while I checked this internally with the engineering team. I wanted to share a clear and transparent update based on their input.
Here’s what’s going on:
• Nikon High-Efficiency (compressed) NEF files are currently not supported on Windows ARM64. This is a known limitation and is documented on HelpX. Because of this, Lightroom (Cloud) and the Adobe DNG Converter are unable to fully read, edit, or export these files on Windows on ARM devices.
• Why Denoise takes ~4 minutes on Windows ARM: On Windows ARM systems, AI Denoise is currently forced to run on the CPU, not the GPU. This is due to stability and memory issues with the existing Windows on ARM GPU drivers. CPU processing is significantly slower, so the behavior you’re seeing is expected and is being actively tracked by our engineering team.
• Why phones/tablets seem faster: Mobile devices do not use the same AI Denoise engine. They rely on classic noise reduction, which is much lighter and not directly comparable.
I understand this is frustrating, especially given the hardware you’re using. I wanted to be upfront with the technical reasons rather than speculate.
If you’d like to help give this more visibility, I strongly encourage you to upvote and share your experience in this existing community thread. The more feedback and upvotes it gets, the more it helps with prioritization:
https://community.adobe.com/t5/lightroom-ecosystem-cloud-based-discussions/p-win-arm-snapdragon-reports-nef-as-an-invalid-file-in-add-photos/td-p/14767580
Thanks again for taking the time to report this and for your patience as Windows-on-ARM support continues to evolve.
Best regards,
Anshul Saini
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