What is that? (“BroadcastListenerWindow” application preventing restart)

Desktop computer: Dell XPS 8700, mfr. date August 2014 so now a little over 7 years. The processor is an Intel Core i7 4790 at 3.60 GHz. 16GB RAM, Seagate “I TB” hard drive, NVIDIA GTX 745 graphics card with 4GB RAM, currently running Windows 10 Pro, version 21H2, build 19044.1503

Originally bundled with Windows 7 Pro, upgraded directly to Windows 10, and last November a repair install of the current version of Windows 10.

It’s on a WiFi home network with a Dell laptop (similar age, same Win 10 version and build), Canon printer, Samsung smartphone.

Internet service by local wireless broadband provider via Comcast backbone, marginal speeds due to distance from wireless base station.

This morning I noticed that my desktop computer was extremely slow – much slower than usual. Opening the apps took several minutes. In fact, I had tried opening several different ones, and several instances of one, before they all appeared on top of each other on the screen. Well, OK, the first thought was to reboot. It probably took me 20 minutes to reboot – and an app was blocking the reboot. I had noticed this crashing in a less dramatic form for the past few weeks, only delaying the reboot for a few seconds, and I couldn’t decipher what the app was. This morning, thanks to excessive slowness, I was able to see it. “BroadcastListenerWindow” was the name. What is that?

To prevent an obvious question: no new updates, other than MS Defender “security intelligence” ones, were installed last night, or for at least a few days prior.

The only “Broadcast” things I listen to on this computer are YouTube music performances. I’ve been a serious pianist and really like Beethoven’s piano sonatas, especially the later ones, so I’m interested in hearing how other pianists play them — with the score in hand, or on display. screen (I’ve played almost all of Beethoven’s sonatas myself, so I’m pretty familiar with most of them). I also watched in the fairly distant past some NPR videos, for example the “Now hear this” series, on composers whose music I know as well (Scarlatti, Bach, etc.). AFAIK, these were also released on YouTube.

After a successful reboot today, install CU preview KB5009596 on both machines as recommended by BC this morning. Desktops and laptops now seem to be running normally, not knowing if they are a little slow or not. I have a slowness-related question regarding installed apps that may be outdated or no longer useful, and other things that may or may not need to run in the background. Am I correct in thinking this should be a separate thread? and if so, in which forum?

Jennifer C. Burleigh