I have recently started re-using and old installation of CS6 ACR to process raw dng files, but it is painfully slow to use. I browse and select the images in bridge with no porblems but when opening them in ACR 9.1.1 It frequently takes several minutes to open the preview of the image, and then a few more minutes before the yellow triangle goes away. Making changes will take ages to refresh on the preview (although the thumbnails will update quickly if more than one image is opened), and often never load at all, until eventually it stops updating completely.
If I cancel (or save) the edits and then re-open in ACR I can do a bit more, at the same snails pace until I finish, or it stops refreshing again.
The issues get more frequent until eventually they will not open at all I need to close bridge completely and restart. It feels like a memory leek or caching issue.
I have installed an even older copy of CS5 on this machine which all work ok, but doesn't have some of the features I need in ACR 9.1.1.
I have tried clearing and increasing the ACR cache but no change.
Windows 10 pro 32bit; Intel Core2 Duo 2.66 x64 CPU; 4GB RAM
Raw files are from a Panasonic TZ200 which are too new to be supported (hence DNG). I have some Sony A77 ARW files that I will try to see if it is file type specific. It seems to handle JPGs ok, but they are tiny in comparison.
My thinking is also about memory handling, but I cannot see why CS5 handles the same files without issue. I would also hope that ACR should be able to handle low memory by queueing (i.e. slowing down) without actually stopping rendering the preview,
Didn't really want to go through the pain of a 64 bit install as I was hoping for a fix, and it seemed like taking a sledgehammer to crack a nut, (there is no 32=>64 bit migration path so a full re-install would be required), but it had crossed my mind.