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Access is Denied Error Message under Windows 95/98

This information applies to users running under Windows 95/98 only.

Whenever I try to run Serialtest Async or Spy, I get the error message, "While trying to open Com X, we received the system error: Access is denied." I don't have any other applications open. Why can't Serialtest use the port?

This message can occur even when it appears that all other applications are closed. We've found that some applications will take control of a serial port even when not using it, and others use helper applications that remain in memory after the main application has closed. To find out what may be running in the background, press Ctrl+Alt+Del ONCE. This will bring up a Close Program window, which shows the applications running in memory. Try closing applications one by one, and try to start Serialtest after each one. To close an application, click on it to highlight it, and then click on the End Task button. Do not close Explorer or Systray, as you need these to run Windows.

A common culprit in these cases is RNAAPP.EXE, which is a helper application used by Dial-Up Networking and which remains in memory for 10-15 minutes after Dial-Up Networking has been used. Article ID Q168222  http://support.microsoft.com/support/kb/articles/Q168/2/22.ASP?LNG=ENG&SA=ALLKB&FR=0 on Microsoft's support site at http://support.microsoft.com has more information about rnaapp.exe.

Some synchronization programs for palmtop computers take control of the serial port when not using it. These programs do not necessarily appear in the Close Programs box, but are usually present in the System Tray in the bottom right corner of the taskbar