I noticed that my Garmin Express (latest version) is gobbling large amounts of memory - I had three versions of older maps on my hard drive (I own Nuvi 2598LMTHD only). If I had terabytes of memory to spare I would not care but with only 128 GB of SSD for both Windows and applications I do care if I see large chunks of memory quickly disappearing. It took me a fair amount of time to research this problem but I finally found the culprit and it is Garmin Express. Your Express product needs some sort of option for memory control.
Garmin Express will store the downloaded map update data in /ProgramData/Garmin/CoreService/Map. It will keep downloads from previous map versions in this directory until Garmin Express is uninstalled or they are manually deleted. If you need to free up space on the SSD deleting these folders will not cause problems in the future.
