Managing Adobe LightRoom ACR Cache

LightRoom (starting from 1.3 as it seems) uses ACR Cache directory for its, well, cache. Those of us who don't have Photoshop CS3 are in fact unable to change the settings of this cache directory easily.

Here is what I found (Windows XP):

1. The cache itself is in:
C:\Documents and Settings\<your acct name>\Local Settings\Application Data\Adobe\CameraRaw\Cache by default.

2. You can delete the files from there as you see fit. Though of course it is better if LR is not running when you do so.

3. There is a file called index.dat in this directory. If you make this file read-only, you will effectively disable the caching all together.

4. However you can do better than this. You can add the following two lines to the file: C:\Documents and Settings\<your acct name>\Application Data\Adobe\CameraRaw\Defaults\Preferences.xmp:

<crs:NegativeCachePath>D:/my_lr_cache</crs:NegativeCachePath>
<crs:NegativeCacheMaximumSize>20.0</crs:NegativeCacheMaximumSize>

You have to place these lines before this one:

</rdf:Description>

Notice the slash direction. The size of the cache is in GB's.

The information has been taken from Adobe Forums.

I hope it will prove useful at least to some of you.