Thank you. I can confirm this works. DPP4 reported spurious mem errors to further confuse the issue. Changing dir name resolved it partially. Also look for files corrupted by DPP4 they typically have a file name DWW or DDW delete them. Extracting from Raw Burst files is a real pain and the resulting CR3 files are different to the ones created by the camera so some applications will not open them. Its a poor implementation of precapture all round really.
