Following Saksham's advice I found that all of the files named "crs:gpu_compute_quick_self_test_passed="False" were already set to "True" but I noticed that within the GPU > Adobe Photoshop Lightroom Classic folder there was a single file called "TempDisableGPU" !!! I then renamed this file Started Lightroom Classic And it seems to work much faster now 🙂 Now, after shutting down Lightroom, I have found that within the GPU > Adobe Photoshop Lightroom Classic folder there is a file called "Camera RAW GPU Config" which is set to "True". I have no idea what I've done, but it seemed logical 'switch off'' the "TempDisableGPU" file by renaming it. And it seemed to work!!!