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[Kurt-Dekker]

It might just require a reimport-all. That’s the first thing to try.

But in general, before you even consider upgrading, you need to make sure the new version Unity even works.

How to troubleshoot build failures:

First, make a blank project with a single blank scene and prove that it builds successfully.

If the blank project does NOT build, go fix your Unity installation or your other tools, such as Android SDK, NDK, JDK, etc. It may even be necessary to change to a different version of Unity3D. It is generally best to stay with LTS versions of Unity3D.

Until you can build a blank project to the target platform, don’t fiddle with anything else.

Once you can build a blank project, now bisect the problem by bringing over parts of your current project and building it one subsystem at a time, perhaps stubbing things out that might trigger compiler errors.

Most often things that prevent building are third-party libraries such as Firebase.

Once you identify the subsystem, go to the documentation for it and make sure you are doing it correctly.

It may also be helpful to work through a tutorial or two for whatever subsystem is making the build fail.

Android build not building:

Recently (circa July 2022) there have been reports of Unity’s installer failing to install the Android Tools.

Can't build for Android

Latest Hub 3.2.0 in combination with Unity 2021.3.6 can't build for Android because there is a missing Tools folder inside *Editor\Data\PlaybackEngines\AndroidPlayer* so Unity can't find gradle. That folder is simply not created during the installation. The workaround is to copy the whole Tools folder from the previous Unity version or if you don't have the previous version then do what [mention|1j+oWeNEPCI6ejbN15sncw==] says in the post below .

Here was how I brought up Unity2020.3.41 and the Android SDK 31 on October 30, 2022:

.AAB Build Targeting API Level 33 on Unity 2021.3.8 with JDK 1.8.

Hey, coincidentally I just upgraded to Android SDK31 today… why not wait until nearly the last minute? It was a wild ride, took most of the day. Let me tell you what I did, what I found. First of all, I’m using Unity2020.3.41 (hereinafter referred to Unity*) because that’s all the further I need to go forward right now. I found that Unity* only accepts up to SDK30.0.3 tools, but will build using those tools and SDK31. Next I found that Android Studio will not install anything except Android …

Android Gradle errors and other related stuff:

Unity Gradle bug... please help

Fix:

ISSUES RELATED TO UPGRADING PROJECTS (eg, changing to a higher Unity version)

Upgrading to a later version of Unity is a one-way process. Any project that has been updated should NEVER be reverted to an earlier version of Unity because this is expressly not supported by Unity. Doing so exposes your project to internal inconsistencies and breakage that may actually be impossible to repair.

If you want to upgrade to a newer version of Unity, do not even consider it until you have placed your project fully under proper source control. This goes double or triple for non-LTS (Tech Stream) versions of Unity3D, which can be extremely unstable compared with LTS.

Once you have source-controlled your project then you may attempt a Unity upgrade. Immediately after any attempted upgrade you should try to view as much of your project as possible, with a mind to looking for broken animations or materials or any other scripting errors or runtime issues.

After an upgrade you should ALWAYS build to all targets you contemplate supporting: iOS and Android can be particularly finicky, and of course any third party libraries you use must also “play nice” with the new version of Unity. Since you didn’t write the third party library, it is up to you to vet it against the new version to make sure it still works.

If there are issues in your testing after upgrading Unity, ABANDON the upgrade, revert your project in source control and be back where you were pre-upgrade with the earlier version of Unity.

Obviously the less you test after the upgrade the more chance you will have of an undiscovered critical issue.

This risk of upgrading is entirely on you and must be considered whenever you contemplate a Unity version upgrade.

Do not upgrade “just for fun” or you may become very unhappy.

PROPERLY CONFIGURING AND USING ENTERPRISE SOURCE CONTROL

I’m sorry you’ve had this issue. Please consider using proper industrial-grade enterprise-qualified source control in order to guard and protect your hard-earned work.

Personally I use git (completely outside of Unity) because it is free and there are tons of tutorials out there to help you set it up as well as free places to host your repo (BitBucket, Github, Gitlab, etc.).

You can also push git repositories to other drives: thumb drives, USB drives, network drives, etc., effectively putting a complete copy of the repository there.

As far as configuring Unity to play nice with git, keep this in mind:

Prefab links keep getting dumped on Git pull

There really isn’t any fix because git works perfectly with Unity when configured properly. Best practices involve saving your work and closing Unity before using git. But if you understand how Unity does and does not flush changes to disk (or at least ALWAYS do a save-project), you can get away with leaving Unity open. The only thing linking EVERYTHING together in Unity is the GUID assigned to a script or asset. Name is irrelevant. Only the GUID connects it. This GUID is in the meta file. I…

I usually make a separate repository for each game, but I have some repositories with a bunch of smaller test games.

Here is how I use git in one of my games, Jetpack Kurt:

2 steps backwards

Yeah, what Praetor said is it… Debug.Log is your friend, and also since this is animation related, you can open up the Animator window when you expect the animations to go, and actually visually see where the state machine is, see which state it thinks it is in. You can combine this with Debug.Log() output at the locations where you set the animations to be what you think they should be, and that should lead you to some intel. I highly recommend setting up git source control. It really plays ni…

Using fine-grained source control as you work to refine your engineering:

When to make a separate object or class/script? Help me think like a programmer! (Example in text.)

This is a reasonable initial approach. The problem is you have listed the parts, but you haven’t really listed how they interact, and even if you did, it’s still sorta up to you how to organize it. Only YOU will know how to organize it, and the only way you can tell is to do the work. I recommend this: first, develop ALWAYS with source control (such as git), and every time you get even the slightest thing working, commit those changes with good commit messages. Then move to the next thing, c…

Share/Sharing source code between projects:

Your techniques to share code between projects?

I have found that bundling your own code into DLLs only serves to slow down your workflow. I base this on several years of experience dealing with other teams well-intentioned packaging mishaps. With games, it is almost always useful to reach into library code, make a temporary tweak to isolate a problem, and then revert it. With DLLs this is impossible, making workflow harder and more brittle. I prefer to share source code at the C# level. That way I can reach into libraries trivially and inje…

Setting up an appropriate .gitignore file for Unity3D:

Removing IL2CPP_cache from Project

Not sure what you are "auto generating" with... I usually start from one of my other projects, or a gitignore example online, and reason about all the parts inside it, and start from there. Like any other configuration change, after you make it, pay attention for a while to make sure it is what you want. You can always clone the repo somewhere else to verify that the correct files are being tracked. Doing so to a brand-new computer is the acid test to make sure you can still bui…

Generally the ONLY folders you should ever source control are:

Assets/
ProjectSettings/
Packages/

NEVER source control Library/ or Temp/ or Logs/
NEVER source control anything from Visual Studio (.vs, .csproj, none of that noise)

Setting git up with Unity (includes above .gitignore concepts):

How to Git with Unity

It is only simple economics that you must expend as much effort into backing it up as you feel the work is worth in the first place. Digital storage is so unbelievably cheap today that you can buy gigabytes of flash drive storage for about the price of a cup of coffee. It’s simply ridiculous not to back up.

If you plan on joining the software industry, you will be required and expected to know how to use source control.

“Use source control or you will be really sad sooner or later.” - StarManta on the Unity3D forum boards

There’s also this noise:

Extra unwanted packages in new projects (collab, testing, rider and other junk):

Temp/UnityEngine.TestRunner.dll Error

Recent versions of unity have an annoying habit of crapping useless packages into your project. When those packages inevitably have errors, this sort of thing happens. I have railed about it before. Go into the package manager and remove crap you don’t need, like the entire test runner and collab and whatnot. If you feel brave you can hand-edit the Packages/manifest.json file a lot faster than using the laggy package manager interface that only lets you remove one package at a time: [7287748-…

About the fastest way I have found to make a project and avoid all this noise is to create the project, then as soon as you see the files appear, FORCE-STOP (hard-kill) Unity (with the Activity Manager or Task Manager), then go hand-edit the Packages/manifest.json file as outlined in the above post, then reopen Unity.

Sometimes the package system gets borked from all this unnecessary churn and requires the package cache to be cleared:

Unity3D Package Cache errors(?)