Application.TickGlobalCallbacks causing issues working in Unity 2020. What is this?

A popup window in Unity with Application.TickGlobalCallbacks frequently, but not consistently, appears while I’m working in Unity 2020.1.1f1. It has appeared after I placed game objects in the scene or just clicked on an asset from the project folders or selected a field to edit in the Inspector pane or applied a texture layer to the terrain. It doesn’t appear every time, but frequent enough to be very annoying.

166600-tickglobalcallbacks.png

All actions have to wait until this window disappears. Most of the time, the popup window disappears within a few seconds, and I can continue working in Unity. Sometimes, however, the window will show an amount of time (e.g., “busy for 8:10”); usually, when that happens, the application never recovers (I’ve waited overnight one time and it still said it was busy the next morning).

I don’t have this issue if I’m working in earlier versions of Unity (2019 and before).

I can usually just search on Google for issues I have, but this one has me stumped. I tried searching for TickGlobalCallbacks but the search returns 0 results.

Does anyone know what this is?

I had the same issues with 2020.1.2f1 recently when trying to attach the debugger to a project after cleaning up a lot of unused script files after some refactoring.

I deleted the Library directory and let it re-generate everything. After that the debugger finally managed to attach after waiting ~2min this time. Not sure if I just wasn’t waiting long enough before… but I’m pretty sure I waited 6min+ and it was still stuck, so may be worth trying to re generate the Library dir.

There will be a few things that can cause this, but this can also happen if you sleep/hibernate the computer, then power back up and try run Unity again, it can freeze or not work properly.

Even with a new process of Unity, if you have just powered up from sleep/hibernate, you will probably see the Application.TickGlobalCallbacks running indefinitely.

You are better to restart the computer for a fresh process.