I did as you instructed, imported a couple more photos, opened and closed LR, and still nothing in the new cache. I checked the disk by opening PS, and it loads its scratch disk info onto the disk. So, the disk appears to be working fine.
The size of the cache is probably subjective but from what I have read then about 10-20 GB is sufficient and not anything near 100 GB. I would do a Google search to find out more on the subject.
If it is not writing Develop previews to the location designated in Preferences, I would expect that it is creating them somewhere else. The question is where. The default location is "C:\Users\user\AppData\Local\Adobe\CameraRaw\"; I wonder if it is writing there despite the Preferences entry.Another possibility occurs to me: Are you converting to the new DNGs with fast load previews incorporated in them. In that case there would be no need for cached previews so LR may not bother creating them.
My file are all tiffs from film scans, with a few jpegs from a p&s camera. No DNGs.
Another possibility occurs to me: Are you converting to the new DNGs with fast load previews incorporated in them. In that case there would be no need for cached previews so LR may not bother creating them.
You just run it again as if it were a raw file. It will just add the option(s) you change.