Problem:

While a program is performing extensive I-O activity on Windows if an attempt is made to do any user input for the program the title on the window changes to "Not responding" and the window gray's out.

Is there a way to avoid this behavior?

Resolution:

Prior to Version 3.2, the runtime automatically processed system events during file operations.  Starting with Version 3.2, this feature was turned off by default, that is why a program can get a "Not responding" screen.

The program still is running and, if the user allows it to finish, the screen turns back to "Responding" mode.

Users can avoid this "Not responding" screen by setting the FILE_IO_PROCESSES_MESSAGES runtime configuration variable to 1 or by using the FILE_IO_PEEKS_MESSAGES variable set to 1.