J.River MC plugin causes MC14 to become unresponsive, locks.

Please can you post here the crash report of the explorer.exe You can find it in the Event Viewer->Windows Logs->Application find the error and post the text here. I guess this is not a real crash but the hang, and Windows restart explorer automatically.

Also maybe there are some other plugins for MC you are using? Try to uninstall the old TLB Remote Control.