NetworkUsageView displays the applications that have been using your network recently, including their name, the time of access for that session, user, internet adapter and the bytes sent and received.
The program doesn't record this information itself, it simply displays the details recorded already by Windows 8 and later. This is sampled hourly and doesn't cover everything, but has more than enough to be interesting.
We ran NetworkUsageView and saw-- a blank table. The readme.txt says we should be warned if it needed to be run as an administrator, but this didn't happen. We relaunched it as admin anyway and this time there was a pause as it loaded and parsed the records, then displayed the results.
Clicking any column header in the table sorts by that field. Clicking "timestamp" gave us an instant timeline of the programs and Windows components that had used our network over the last 9 days.
Sorting by "App Name" grouped together all the logged sessions for each app. This can produce some surprises. No-one used Skype on our test PC, but the Microsoft.SkypeApp process still recorded 87 network sessions.
Beware: there might be some disappointments. We found some processes - including the two responsible for downloading more data in a single session on our test system - had no app or user details, giving us no idea what they were.
We would guess there are also some cleanup tools which delete this data, or perhaps stop Windows collecting it. If you've used one of those it's likely NetworkUsageView won't have anything to show you.
NetworkUsageView is yet another neat NirSoft tool which provides genuinely useful information you can't easily find in any other way. If you're worried about malware, looking for resource hogs or just generally troubleshooting your PC, take a look. But remember, run it as an administrator (right-click "Run as...").