I'm experiencing huge performance regression in entering the play mode if the project has a lot of sprite atlases / PSB files even when running an empty scene. I'm using the new "Enter Play Mode" settings to prevent scene/domain reload. In our project we're now at 17+ seconds on our fastest machines (8700K, 64GB RAM, SSD). This is completely destroying our process and is making it really hard to work. It all seems to come from Unity not caching the atlas bakes in the memory and loading them from disk constantly: And then there is this new annoying "Hold On" message that is adding to the wait without seeming doing anything in the background. It even shows up when I'm trying to delete a few files or move around assets: I had high hopes for the new Asset Pipeline to improve our import/load times, but I think sacrificing the "Enter Play Mode" speed and other immediate tasks inside Unity for it is a very bad tradeoff. I would gladly wait longer for the project to load than having to wait 17 seconds each time I hit the Play button or 10 seconds to remove a few files. I thought that this is because our project is too big (which runs fine on older Unity versions), but even an almost empty project shows this before running the game. I hope this is just a bug and not "By Design" and gets fixed before the beta phases ends, because it would make it really painful to work in Unity.