What did the mysterious avast message say?
Hi Pondus,
That was a quick response!
The Avast report just listed three devices as follows:
1: my computer with its IP address, Mac address and a "no services detected" message;
2: my modem/router with its IP address, Mac address and the detected service;
3: the unknown device with its IP address, Mac address and a "no services detected" message.
Each list item received a green tick with the message "no problems found on this device".
I also received a general "Congratulations ...... " message.
The mystery has now deepened as I ran the 'Network Threat' scan while I was typing this replay and guess what, that unknown device was not listed although it appeared in two other scans I ran after it was first detected this morning.