In answer to Richard, it's just NWC which suffered from the problem, and Rick has provided the information I needed to solve it. At some point I moved some of my profile folders to another disk, including the %APPDATA% folder. However NWC had remembered the expanded location
I'm running NWC 2.5.5 on Windows 7 64 bit, and every time I start up the application, the File>History... list is empty (files are added to the list during a session, but closing & restarting the application clears it again). Does anyone have any ideas how I might fix this?