I've been working in a project some weeks now in a Mixed Reality project using Unity and MRTK and I've found a strange behaviour when adding screen capture to the application. I'm using Unity 2019.4.26f1, and I haven't found any issues so far but after adding this line of code
ScreenCapture.CaptureScreenshot("test.png");
into a script, I've realised that when I press Play and go into Game mode, everything goes correctly (the game starts, the screenshot is taken). BUT when I stop it and try to go into Play mode again, Unity freezes. If I don't press Play again, Unity still works until it tries to compile scripts or some heavy task like that, when it freezes and can only be closed with the task manager.
If I remove that line, Unity goes back to normal.
This issue cannot be reproduced in Unity 2020.3 LTS. Does this happen when the remoting play or in Editor? According to Choosing a Unity version and XR plugin - Mixed Reality | Microsoft Docs, if you target to HoloLens 2, please upgrade to the recommended 2020.3 LTS version that is stated in the document.
In addition, ScreenCapture is a Unity built-in class and if there are any usage questions, you may find support from Unity forum.