Panorama merge issues.

Hi all, I have been creating grand vista panoramas for years with no problem, as long I have done everything correctly in camera, but after a recent trip to Scotland where I shot loads of pano's I returned to encounter problems, the main one being after the images are stitched together and I see the preview all looks good but when I actually click to merge them the status bar gets to 100% then they disappear instead of showing as a final fully merged pano image for me to edit if necessary in develop, does anyone know where they might be going because I can't see them anywhere?