Camera Raw Cache taking up >100GB

Report · Jan 20, 2018

Beware of lightroom's cache.

I moved a number of images from my internal HD to an external, using Lightroom. The process completed, the photos had been happily relocated. However, my internal HD was just as full as it had previously been. The trash was empty, and the images were no longer in their previous location. I had a little look at lightroom's performance settings (under preferences) and there were a number of cache settings. Under "Camera Raw Cache Settings" there was a maximum cache size of 5GB set - so I thought it was unlikely that this was a significant factor but I thought it was worth a go, and to my surprise this resulted in over 100GB of disk space being freed up! So if anyone is experiencing the same issue that is definitely worth a go.

Report · Jan 20, 2018

I set my ACR cache to 200GB, because the acr cache files for my 170,000 images take up over 150GB of space. If you restrict the space, then the cache simply deletes the oldest files to allow for new ones. I want all my cache files to be kept. No idea why your cache should have been over 5GB if that is what you set it at, but there are all sorts of bugs in LR - always have been, always will be. We just have to learn to live with them!

Bob Frost

Report · Jan 21, 2018

Update: Lightroom turned out not to be the culprit on this occasion. I was mislead by OSX's calculation of free space, and some odd behaviour around timemachine backups. It turns out, when I moved the files from one disk to another timemachine made a local backup of everything that I had moved. Timemachine likes to keep this cache hidden, making it very tricky to track down what is eating up your disk space. For anyone having this issue I recommend reading the thread below.

High Sierra disk space over 120Gb |Official Apple Support Communities

`sudo tmutil thinLocalSnapshots / 10000000000 4` fixed it for me in the end, but make sure you've read the thread before trying that.

So, my apologies to Lightroom - not the disk space eater that I suspected it of being!