I'm having an issue where lightroom creates an insanely massive tmp file and fills up my hard drive space. The photo cache is set to 5gb, but some times I can find a 40gb+ tmp file in my local temp files.
This is what my C: drive looks like before an HDR pano merge.
This is what it looks like after 1 merge. About 50 photos in that one merge. I have to close lightroom and manually delete this block if I want to do any more photo merges. It gives me an error not enough space message each time.
Here is what windirstat says about the file. This file size is insane and almost 40x times as big as all of the original RAW sizes combined.
I also get a cr_sdk file in the same location as you. But I'm not doing photo merges (believe i was building 1:1 previews). Windows says it still has free memory during (and after) the operation.
Anyone know the cause of this file?
LrC CATALOG LOCATION:
CAMERA RAW CACHE LOCATION / SIZE ALLOWED:
Note, the location for the catalog and the location for Camera RAW CACHE, can take advantage of drive speed, the location of photos does not.
Note, the Library preview files cannot be on a different drive than the catalog.
OS TEMP FILE LOCATION
I'm not sure why you're so surprised at the size of this file. Of course it will be big. 40 GB doesn't seem unreasonable to me. If you use Photoshop, you'll know that 40 GB can be eaten up in an instant when you work with big files.
Where I do agree with you, is that it should be possible to move temp files to a disk of your choice. Like Photoshop, where you can put the scratch disk wherever you want. That's not possible with Lightroom, and I believe the reason is that Lightroom doesn't have its own memory management. So it has to use the OS pagefile. I suppose it was never really necessary - until now when you can make these huge panos.
Under normal operation, excluding panos, Lightroom doesn't really use or need a lot of memory.
So while I would certainly support this as a feature request, I suspect it's not really easy to implement. The Lightroom architecture currently doesn't have the tools.
All that said, you really are living dangerously with only 40 GB free on the system drive. A "standard" configuration of operating system and applications shouldn't take up more than around 90 - 110 GB, so there is room for some cleanup there. Here's my system drive, and I have 6 major CC apps installed. All app caches have been moved elsewhere: