Device Manager enumerates a 'Serial' device on your legacy-free Windows XP or Windows Server 2003 computer.
If a yellow exclamation point is displayed next to the 'Serial' device, Device Manager displays:
The device is not present, is not working properly, or does not have all its drivers installed. (Code 24)
This behavior occurs because HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_SERIAL exists in the registry, causing Windows to test for a serial port. If no serial port is detected, Device Manager shows the 'Serial' device. If some process tries to start the 'Serial' device, the yellow exclamation point is also displayed.
NOTE: Code 24 is an informational message, NOT an error.
Since no error exists, you do NOT have to take any action.