"""Thanks for reporting the issue. We are reviewing it.

In the meanwhile, here is a workaround that might help to overcome this issue: Turn ON Application Frame (Window > Application Frame).

-InDesign Team""

This does not help. Free Flow or Application Frame, the red bars appearing. The right solution is turn off GPU acceleration. At least for me on my expensive Mac Pro. please see here:

https://community.adobe.com/t5/indesign/indesign-16-2-1-showing-red-bar-on-workspace/m-p/12057532#M430286

Operating System – now Mac Os 11.4,
(MacPro Vega Pro II Duo.
3,3 GHz 12-Core Intel Xeon W
48 GB 2933 MHz DDR4
1TB SSD)
Are you using any eGPU and external monitor? NO eGPU, 1xMPX Apple Vega Pro II Duo - YES, external Monitor Displayport (otherwise i can see anything on a MacPro2019)
Does turning on Appliation Frame (Window > Appliation Frame) helps resolving the issue? – i'm working in Application Frame mode – disabling Application Frame however helps to remove the red bars temp. BUT, as soon as I "tab" all open indesign windows/dokuments in one window and switch through them red bars appear again.
What all applications are running in the background? – Photoshop, Illustartor, zoom, Spark, Finder, Safari.
Does turning off GPU performance as suggested by Bob helped resolving the issue? – yes, as soon as i click gpu off.

To fix and see document/work the window must be resized from corner anchors or is stuck and unusable however you zoom in or out

I'm also encountering this problem with Indesign 16.2.1, even when Application frame is turned on. I only get red bars, not black. Resizing the window occasionally makes it go away, but it always returns. Even stranger, if I have multiple files open it doesn't immediately happen to them all.

Soon after the red bars appear I'm also not able to select and move objects in my document or the cursor doesn't accurate select things (I almost have to click above an object to select it). Restarting Indesign and reopening the file seems to temporarily correct it.

Big Sur 11.3.1
MacBook Pro (16-inch, 2019
2.4 GHz 8-Core Intel Core i9
32 GB 2667 MHz DDR4
AMD Radeon Pro 5500M 8 GB
External LG monitor

This is happening to me too! Turning off GPU has sloved it but need to use the GPU for faster rendering really - Alos have the same problem in photoshop although there it just freezes. When you go to adjust the window size of an image it stretches the entire image instead of just cropping it or widening it. Again if you turn off the gpu this isnt an issue. I was thinking it was something wrong with my graphics card or something? But if anyone knows of af ix for this as well let me know. As its so slow when not using GPU in photoshop.

Thanks

"Turning off GPU makes the problem go away, so have done that for now." … This helped a lot! Thank you, anonymous guy from below! <3

I'm having the same problem on my iMac Pro 2017, OSX 10.15.7, thunderbolt connected LG HRD 4K screen as main monitor. Running Indesign 16.2.1.
Dragging/resizing window fixes display
Turning off GPU makes the problem go away, so have done that for now.

When I open an InDesign file in 2021 16.2.1 (CC says I'm up to date), nothing appears, or if it does, it's a faint glimmer of what the file should be. I try to zoom or scroll, it creates random blocks of color. There's zero usability. I've tried opening several files, all yield the same results. Also tried relaunching, restarting etc. I'm running Mojave 10.14.5

Having install 16.2.1
opening files means that you cannot move from the opening page view to another
or progressive black band appears from bottom or top of screen

Hi,

I have exactly the same problem here after the 16.2.1 update. Also MacBook 16" 2019, but running with Catalina (10.15.7). As you've stated, the issue is with the initial window rendering only (on every new or loaded document, though) and it goes away by using the mentioned procedures. But yes, this is annoyin and I hope it gets fixed soon.

Since the 16.2.1 update I have this problem that all documents doesn't render correctly on external Apple Thunderbolt Display.
• Turning off GPU-performance makes the problem go away.
• Switching to CPU-performance and it works.
• Dragging the window to the MacBook Pro internal screen and then back to the Thunderbolt Display and it works.
• Pressing the window maximise button and it works (if I first press shift+tab to hide panels).
• Resizing window and it works.
But really annoying bug with this red and faulty rendered document everything time I open or create a new document.

Big Sur 11.2.3
Indesign 16.2.1
MacBook Pro (16 tum, 2019)
2,4 GHz 8-Core Intel Core i9
AMD Radeon Pro 5500M 8 GB