Unity 2021.3.29f1 can't build on android

[Gailbert]

Hi

I switched Unity version from 2021.2.5f1 to 2021.3.29f1 and I’ve been getting this error when I try to build with Android. I’m very new to forums if there’s anything I can provide more please let me know.

Thank you in advance!

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Android.PostProcessor.Tasks.Initializer.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context) (at <53a24fd937e24f249a40af7ff60927ab>:0)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context) (at <53a24fd937e24f249a40af7ff60927ab>:0)
UnityEditor.Android.AndroidBuildPostprocessor.PrepareForBuildProgram (UnityEditor.Modules.BuildPostProcessArgs args) (at <53a24fd937e24f249a40af7ff60927ab>:0)
UnityEditor.Android.AndroidBuildPostprocessor.PostProcess (UnityEditor.Modules.BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at <53a24fd937e24f249a40af7ff60927ab>:0)
UnityEditor.PostprocessBuildPlayer.Postprocess (UnityEditor.BuildTargetGroup targetGroup, UnityEditor.BuildTarget target, System.Int32 subtarget, System.String installPath, System.String companyName, System.String productName, System.Int32 width, System.Int32 height, UnityEditor.BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport report) (at <1e8c82ffe64a4e1d8e997fa7e5933f70>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)

[Kurt-Dekker]

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:

[Gailbert]

@Kurt-Dekker

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.

https://discussions.unity.com/t/887277

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

https://discussions.unity.com/t/891017/7

Android Gradle errors and other related stuff:

https://discussions.unity.com/t/901712/2

Hi Kurt-Dekker,

I did the new project, blank scene thing and unfortunately I got the same error.
I installed 2021.3.29f1 with the recommended JDK and SDK with it.

I will try installing the latest unity version.

[Lorrak]

Solution, select “Target API Level” the last level, then Unity Editor will do small update? Restart Editor, change target api level back(or to target highest), build your project

this should be sticked