I am also having this issue during the Aligning Images step. The first time it happened, I let it run for nearly 15 hours but never made progress past 21%. I tried to abort, but RC would never stop, so I ended up having to shut down RC through the Task Manager. I restarted RC and tried again, but again it stalled at 21%. I am trying to align 5335 images. All goes well until the Processing step gets to 21%, and then it stalls. When it gets to 21%, the CPU drops down to 0.5%, Memory is at 88%, and there is still Disk activity at about 12 MB/s.