This can happen if a file in your Auto-Import Watched Directories is corrupt and the import analysis gets stuck on it.
If you have
Process Explorer installed (if not, you can download and install it because it is free and very handy), you can use it to check what handles the Media Center process has open. Launch MC and let it run a while until it consumes a bit of RAM. Then, use Process Explorer
to see what specific handles MC has open at any moment. If you see a ton of handles for a single file (or set of them), then there is a good chance those files are broken in some way.
If you find a file that otherwise seems to be fine but which trips up MC's Auto-Import, the JRiver developers would typically love to get a copy of it to see what is causing it to go sideways. In all cases I've ever seen, it was because the file was horribly borked and needed to be deleted.
