The LR cache folder isn’t the Camera Raw cache folder. The CR Cache folder contains information about the demosaicked raw files that both LR and PS/ACR use when doing adjustments to raw images.
The LR cache folder contains several subfolders for different purposes. The most troublesome is:
C:\Users\username\AppData\Local\Adobe\Lightroom\Caches\Video\Media Cache Files
which is added to whenever you do an Import from somewhere that has video files. For each video file on the prospective Import path AND its subfolders, there will be a large audio file (cfa) and a small pek (peak) file. This helps speed up video conversions in LR, but the problem is that any folder you click on while you’re navigating to your Import source will see all the video files under it even if you never import them. In other words if you click on C:\ when navigating to your destination, then all the video files on your entire C drive will get cache data built for them. And this data seems to stay there unless you manually remove it. I’d suggest you delete everything in the Media Cache and Media Cache Files subfolders and see if it comes back.
Since this cache data is built when you import and not when you work on the photos, the difference sizes are because different video files have existed on your import sources on the two computers.
Thank you. That was all very good information.
I took your recommended actions early today, but waited to make sure that I did not have any surprises as the day progressed. I deleted all files in the Media Cache and the Media Cache Files subfolders. Almost 100 GB worth.
Those folders are still empty several hours later, even though I have worked in Lightroom probably 2 hours today. But I have not performed an import, which would likely have brought those folders back into play.
I guess that means that I need to purge those folders after a period of importing ? Assuming I import across folders that have video files in any of their subfolders?
There is no way to change the destination folder for those cache files? To possibly a large USB HD ?
Thanks once more.
You cannot specify where this cache is, no.
However, you can delete what's in it via the LR interface, it's only the size limit doesn't have any effect for files placed there during the Import scan, because a non-LR process is what's putting the files there, the DynamicLinkMediaServer.exe It is possible to rename/delete the executable to stop videos from being parsed into that location during Import, but then your video processing may not work as well, I'm not sure. I rarely do videos in LR.
I just bought the LR 6 for Mac, and the Video Cache Settings area you've highlighted in the screen shot does NOT work. On my Mac, the maximum setting was 3.0 GB while the directory (which I had to hunt for methodically sizing each sub directory until I narrowed down the culprit) had 202 GB of video cache files. The LR app is NOT abiding by caching size set in this dialogue. Clicking the "Purge Cache" button did nothing. Directory size remained at 202 GB.
From my searching, this is a known and huge bug in the LR software. Very nearly killed my hard drive last night, caught the process with only 25GB free space on my Mac hard drive.
I had the exact same issue on my Window 10 desktop. It nearly killed my Smaller Solid state drive (C:) even though I was storing my catalog and files on separate hard drive (D:), I never realized it created this massive video file cache on the main C: Drive. I did "purge" the within the LR Preferences section and it seemed to remove the cache files with no problem.