Today’s Question: My internal hard drive was starting to fill up so I went looking for large files that I could delete. I found that I have two Adobe Camera Raw Cache folders. The first which contains 54.2Gb of data was last modified on 11 Dec 2018 and the second was created on 12 Dec 2018 and contains 27.6Gb of data. I assume the second cache was created following an update to Lightroom. Can I delete the older cache folder and its data, and if so what is the safest way?
Tim’s Quick Answer: You can delete the Camera Raw Cache folders without creating any problems, other than possibly slowing down the browsing of photos that have been modified either in Lightroom or directly via Adobe Camera Raw (for Photoshop users). In this case you probably only need to delete the older cache, but if you delete both a new cache folder will be created automatically as needed.
More Detail: A cache file is generally a temporary storage location to help improve performance for a given software application. As such, it is generally safe to delete any cache. Since the cache is created in the first place to improve performance, the only potential negative side-effect of deleting a cache would be slower performance when that cache can’t be leveraged.
When you removed an outdated version of Lightroom (or Photoshop), old caches would typically be removed. I suspect in this case there was some sort of glitch that caused the cache to remain after the software was removed, or that the older version wasn’t in fact removed.
Note that the date for the folder does not reflect the age of the cache. I suggest looking inside the cache folder to see what the most recent file dates are. In this case the older cache folder most likely only contains older cache files that are no longer necessary.
I suggest making sure the Lightroom (and Photoshop) are not running when you delete the cache folders. You can then simply delete the entire folder from your hard drive. Once your Trash (Macintosh) or Recycle Bin (Windows) has been emptied, the space that had been consumed by the cache will be freed up.
Note that if you delete both cache folders Lightroom (or Photoshop) would simply create a new cache folder as needed. Therefore, as noted above, there isn’t any risk of deleting a cache that had still been in use, other than a potential degradation of performance.