Portfolio Could Not Open An Investment File:
Portfolio files (*.mm4) store the relative path and filename of all the investments in all sub-portfolios. If an investment file is renamed or moved outside of Fund Manager, your portfolio will no longer be able to locate the investment file. If this happens you will be prompted to find the new location of this investment.
The path of investment files (*.dat) are stored relative to the portfolio file (*.mm4) itself. This allows you to safely move both investment files and portfolios to a new folder, as long as you keep their relative path the same. For example, if you have your portfolio and investment files in the same directory, you can move or rename that directory without affecting the relative path.