Windows only permits one program to access a COM port at a time. When a radio control application is running it will normally require constant access
to that COM port to monitor for things such as frequency or mode changes. While the radio control program has the radio COM port open, ICOM 7300
Memory Manager will not be able to open that same port to communicate with the radio.
Some radio control applications provide a 3rd party integration or virtual COM port feature. By design this type of integration doesn't
provide access to all of the CI-V commands used by ICOM 7300 Memory Manager. Since most radio control applications already provide access to the
radio's memories the memory commands are usually not included in this type of integration.
If you still want to be able to access the radio using multiple applications simultaneously, the ICOM 7300 has both a USB COM port as well as a
back panel CI-V connector. It is possible to use both of these ports at the same time. You would need to set Unlink from [Remote] in the set
menu under Menu/Set/Connectors/CI-V and use both a USB and a CI-V cable. Then you could run one application using the USB cable and a second
using the CI-V cable. Another option would be to use a serial port splitter, either software or hardware.