I am editing a large batch of 3 exposure HDR images and all working perfectly with about 15 pairs and then stopped working. I get the following message "Unable to merge photos. Please cancel and review your selection."
What can cause a well used feature to suddenly stop working in the middle of a job? I have tried restarting LR, optimising the catalog and also restarting the PC (Win 10 Pro).
PROBLEM SOLVED BY REINSTALLING LIGHTROOM!
Thanks for the update.