[R] Loadhistory problems

[Robert Brown FM CEFAS]

History files saved using nFile Save History do not open when using File Load History. I notice that when they are saved they do not seem to have a file extension and there is no option to chose an extension.  Is this a problem.  Other than this it seems so simple that I can't see what the problem is.    I've tried using loadhistory and savehistory with the same problems.  The syntax guide for load history requires the file name, but doesn't specify if this should include and extension or what this should be.  Where am I going wrong