I'm a Zoom host, using Windows 10 Home on a laptop. Sometimes my participants complain about seeing solid gray rectangles on their screen. This happens when I share a process that is showing an image or video full screen. These boxes could be caused by various windows on my computer: the two rectangular Zoom meeting control rectangles, the Zoom Participants box, the Zoom Chat box, or other apps such as file explorer or browser. When I share a full screen image or video, I want my participants to see only that, not additional overlaying gray boxes. Is there a setting for this? If not, when are the gray boxes shown and when are then not shown? Note: web searches show no information about gray boxes or rectangles caused by Zoom.

  • 1
    Some screenshots would help to figure out what is going on. Is only the other end seeing the grey boxes? If so the problem may have nothing to do with you ... – DavidPostill Jul 2 at 15:36

I am not a developer, but this issue has been plaguing us as we run a video for participants but also need to monitor the chats and participant windows. The only people who can see the issue are participants. The host sees their normal windows which tend to be persistent and pinned on top of the other zoom content. Normally these windows are simply hidden entirely from the view of the participants during other screen share modes with video optimization turned off. No placeholder gray boxes or anything.

Turning off the optimization is a workaround and not a solution as it leads to syncing issues with the audio and video. That workaround may be fine for others, but it does't work for us and doesn't seem to be an intended solution as it is only a problem on the Windows 10 platform as far as my Google searches have revealed.

Our workaround has been to have the host log in on a second device and monitor the chat and participant windows from there. We can hide all of the zoom chat/participant windows and hide the floating settings window.

This is not happening on our Mac OS devices. Just the Windows 10. It doesn't seem to be a feature. It seems to be a bug or an implementation issue on Windows 10.

| improve this answer | |
  • This is interesting. Exactly how does having a second device login to monitor the chat help you to hide the solid gray boxes? Please explain, as it isn't obvious to me, thanks. – David Spector Jul 7 at 19:16
  • David, we hide the boxes on the device using the screen share using the zoom options and then on a second device, log in a second time on the same account and monitor the chat and participant windows from there. – Ryan Jul 8 at 13:28
  • Ryan, just to confirm, you're agreeing with my answer above that the key is turning off the "optimization for fullscreen video" checkbox unless we are willing to keep the screen absolutely free of other windows? – David Spector Jul 9 at 14:23
  • Your answer is not a solution because it requires a second person to assist the host, ideally sharing the hosting role so administrative/security actions can be done. For many meetings, no such second person is available. My answer at least eliminates the gray boxes in those cases where we don't need the video optimization feature. – David Spector Jul 15 at 9:50

We've been running Zoom meetings for about 3 months now, we encountered those boxes several times and one of the best solutions we found to get rid of them was the same as Ryan's solution, which is to share screen from the laptop and control the participants from another device (smart phone).enter image description here

| improve this answer | |

I figured it out myself, with some experimentation, running as host and participant in the same meeting. The solid dark gray boxes are clearly a security mechanism by Zoom to prevent participants from seeing other windows on top of the shared window.

Why should participants be able to see other windows, you ask? Well, it's simple and complicated at the same time. Instead of simply sending the video being shown directly to the participants, Zoom intercepts the hardware to capture the data as it is being displayed. So you see the topmost shared window AND any windows that are on top of it! Graying out the window prevents participants from seeing whatever the host is doing, for security.

So the solution appears to be pretty simple: just turn OFF the "optimize for showing video" option. Then Zoom simply sends the shared window, again and again (at 6 to 30 frames per second, depending on source and destination bandwidth) to the participants and ignores other windows. In fact, with Optimization off, you can even minimize all windows and/or return to the desktop, and the participants continue to see the shared window only.

For the Zoom meetings I host, I want the best experience for my participants, so I set up muting and other options the way I want, then I show the video in a video player, share the player output, and optimize it. I make sure that all other windows are never displayed on top of the video on my screen while the video is running, and I keep the cursor at the extreme lower right so it is not seen. I avoid any use of the cursor or of Zoom features while I am playing a video. This works perfectly for me, because we don't use chat or other features when playing videos.

| improve this answer | |

Even if I do turn off the chat, the floating control panel, and the participant window, if I am screen sharing a video, and am sharing sound and video( by clicking those boxes in the screen share screen) any time a participant is booted, or arrives late, they land in the waiting room, the floating control bar comes back, and box appears notifying me that someone is in the waiting room greys out the attendees screen...This has only become an issue when Zoom removes the ‘disable waiting room feature’ recently. Prior to that once the meeting began I could disable the waiting room, so if people got booted, and/or arrived late, they could just re enter without me having to deal with it, and without it interfering with my attendees experience.

Why oh why are we no longer permitted to disable waiting room?? The would resolve more than one issue I am currently having with Zoom.

| improve this answer | |
  • Dear Susan, it would be a good idea if you turned your answer into a comment. Answers and comments are treated very differently here at Superuser. As to your complaint, a good idea would be for you to send it directly to Zoom. You'll have to figure out if they have a reporting website or a community forum that you can use to do this. You can also setup your meeting WIITH a password and WITHOUT a waiting room, so new arrivals will join the room silently. So, my main recommemdation is that you delete this answer before it is downvoted. This can limit your future ability to use this service. – David Spector Nov 14 at 18:08

Read the "Advanced share screen options" setting on this page: https://support.zoom.us/hc/en-us/articles/360037870291-Advanced-desktop-client-settings

There is an option to "Share selected app window only" that you can turn on. And there are also screen capture modes that "capture with window filtering" which claims to not show windows from the Zoom client.

| improve this answer | |
  • Thank you for your suggestion. However, when optimizing video, the entire screen is sent to your Zoom meeting. So any Zoom or other windows that are displayed on top of the screen will be sent as gray boxes to your participants. You either have to keep ONLY the video on the screen, or don't optimize video. – David Spector Nov 5 at 13:51

i found a solution of zoom gray boxes problem. https://youtu.be/CRCCWBLPhlk

| improve this answer | |
  • Welcome to Super User! Please quote the essential parts of the answer from the reference link(s), as the answer can become invalid if the linked page(s) change. – DavidPostill Nov 4 at 17:43
  • The video is crazy. First is sets the Optimize Video option and then it clears it. It also shows lots of irrelevant stuff. To eliminate gray boxes, when optimizing a video, you must make your video full screen, turn off any other windows or panes, and keep your mouse cursor off the screen. Or, just don't optimize the video. – David Spector Nov 5 at 13:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.