When I click to open a *.xmcd file, MC does not open. Instead I get one or more error messages. There are two related behaviors depending on whether the path has spaces in it or not. For a path with spaces: Two errors. One says "Windows cannot find '<path>'. Make sure you typed the name correctly, and then try again. To search for a file, click the Start Button, and then click Search." The other message from Mathcad says "<truncated path> was not found". I already tried open with and selected the MC executable, checking to always open with that file. The result was the same except that there was no windows error, only the Mathcad error with the truncated path. The file opens OK if I first start MC, then open from within MC. For a path without spaces: I get the windows error message, but MC does start and the file does open. Thanks for any comments and help. Dave