Are you referring to environment variable MCR_CACHE_ROOT ? I'm not aware of a variable called MCR_CACHE_MEMORY If you are referring to MCR_CACHE_ROOT, then your compiled/packaged application will run (i.e. extract first) and then the extraction dircetories stay until you are done with your application and you no longer wish to use it or run it. You must manually delete this directory when done using (unless you dont care that it lives in a temporary directory). The idea being that your extracted directories contain all your files needed to run your application (apart from thirdparty files that you assume are already found on your target host or any mathworks licensed files such as the matlab runtime files)
These doc links may help in understanding what is going in with the extraction:
https://www.mathworks.com/help/compiler_sdk/ml_code/mcr-component-cache-and-ctf-archive-embedding.html https://www.mathworks.com/help/pdf_doc/compiler_sdk/compiler_sdk_matlab.pdf
