Many thanks for your reply. 'Use graphics processor' is already unchecked. Below is the info from my system info, I updated the software yesterday in the hope this may solve it but hasn't, the problem persisted on the previous version too. Lightroom Classic version: 8.3.1 [ 201905241238-dcd7e2de ] License: Creative Cloud Language setting: en-GB Operating system: Mac OS 10 Version: 10.14.0 [18A391] Application architecture: x64 Logical processor count: 4 Processor speed: 3.2 GHz Built-in memory: 16,384.0 MB Real memory available to Lightroom: 16,384.0 MB Real memory used by Lightroom: 1,848.7 MB (11.2%) Virtual memory used by Lightroom: 5,191.2 MB Memory cache size: 290.2MB Internal Camera Raw version: 11.3 [ 197 ] Maximum thread count used by Camera Raw: 3 Camera Raw SIMD optimization: SSE2,AVX,AVX2 Camera Raw virtual memory: 767MB / 8191MB (9%) Camera Raw real memory: 768MB / 16384MB (4%) Displays: 1) 2560x1440 Graphics Processor Info: Metal: NVIDIA GeForce GT 755M
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