Unity Stuck on Resolving Packages.

I am having the same issue in 2021.3.29f1.

I find a workable solution: find your Editor.log and search for "immutable" to find logs like this:

"The package cache was invalidated and rebuilt because the following immutable asset(s) were unexpectedly altered:
Packages/com. Unity. Testtools. Codecoverage/Editor/Icons/codecoverage. PNG "

The packages listed here is the cause of PackageManager infinite resolving. Just remove these Packages from the PackageManager (or find package name in mainfest.json, since some of packages do not show in package manager), than all seems to be fine. I'm not sure why, but it does work for me.

 

So, I can't upgrade to the latest Unity Editor for this because VRChat only currently supports 2019.4.3. The Editor won't start, so no check mark to clear. After HOURS of beating my head against the keyboard, and deciding that it was a package thing, I started messing around with the <projectRoot>/Packages/manifext.json dependencies. The Importing windows spawned by the VRChat CreatorCompanion told me which dependencies were taking too long to download, so I'd remove them from the manifext (kinda like a maven pom.xml I guess). That was not working, and I have probably removed packages that I'll need later, so being that it was a package download problem (the Unity Editor opened lightning fast from the Unity Hub with no packages installed), I decided to downgrade the "Official" "VrChat Package Resolver Tool" from the latest 0.1.21 to the lowest 0.1.6. Voila! Lightning fast opened editor. VRChat really needs to fix that "Official" package management tool, or at least remove the buggy version(s). I've wasted so much time and haven't even gotten started!... I'm a pro dev by the way, so this is not a noob problem. I'll also post this on the VRChat forum. Just noticed that this is actually a Unity forum. If this is happening with other games/experiences I'm not sure that this helps anyone, except to maybe make a copy of that manifext.json file, then remove everything, adding back one by one till the editor breaks, then you have found your culprit. Or... if you can get the Editor to open after removing the dependencies from the manifest, maybe then you can disable the "Install toolchain package automatically" under the ProjectSettings menu, and maybe add back some or all of the dependent packages to the manifest so that they will download.... that is unless disabling that functionality keeps Unity from downloading via manifest. Happy Hunting!

 

Did it and totally messed up my project. Not only didn't it fix anything but I get errors that There's no TMPro or even UI!

 

Problem Solved! The reason is our project using CustomAssetImpoter to modify asset when importing asset, but it does run even importing assets through package manager. Before modify assets in CustomAssetImpoter, skip assets which path is outside "Assets/".