"Random" Gradle build error: java.io.IOException: Could not create empty folder

I'm using new gradle build and custom mainTemplate.gradle and library.gradle files to build Android apks for my game.
Most of the time the build is successful as I managed to fix the issues with Manifests or resources or dependencies.
However sometimes I get this error:

java.io.IOException: Could not create empty folder

It occurs every time on a different gradle task for a different library.
In some cases, closing and opening Unity or removing Temp folder solves this.

Any idea how to solve this?

 

Spoiler: Editor.log

Android PostProcess task "Creating staging area" took 11.5059 ms
Android PostProcess task "Generating Build Id" took 3.1051 ms
Android PostProcess task "Preparing Unity resources" took 41.6555 ms
Android PostProcess task "Splitting assets" took 10.6974 ms
Android PostProcess task "Processing OBB assets" took 0.3076 ms
Android PostProcess task "Preparing Unity libraries" took 206.6238 ms
OBSOLETE - Providing Android resources in Assets/Plugins/Android/res is deprecated, please move your resources to an AAR or an Android Library. See "AAR plug-ins and Android Libraries" section of the Manual for more details.
UnityEngine.DebugLogHandler:Internal_Log(LogType, String, Object)
UnityEngine.DebugLogHandler:LogFormat(LogType, Object, String, Object[])
UnityEngine.Logger:Log(LogType, Object)
UnityEngine.Debug:LogWarning(Object)
UnityEditor.Android.PostProcessor.Tasks.PrepareUserResources:Execute(PostProcessorContext)
UnityEditor.Android.PostProcessor.PostProcessRunner:RunAllTasks(PostProcessorContext)
UnityEditor.Android.PostProcessAndroidPlayerostProcess(BuildTarget, String, String, String, String, String, String, BuildOptions, RuntimeClassRegistry, BuildReport)
UnityEditor.Android.AndroidBuildPostprocessorostProcess(BuildPostProcessArgs)
UnityEditor.PostprocessBuildPlayerostprocess(BuildTargetGroup, BuildTarget, String, String, String, Int32, Int32, BuildOptions, RuntimeClassRegistry, BuildReport) (at C:\buildslave\unity\build\Editor\Mono\BuildPipeline\PostprocessBuildPlayer.cs:263)
UnityEditor.BuildPipeline:BuildPlayerInternalNoCheck(String[], String, String, BuildTargetGroup, BuildTarget, BuildOptions, Boolean)
UnityEditor.BuildPipeline:BuildPlayerInternal(String[], String, String, BuildTargetGroup, BuildTarget, BuildOptions) (at C:\buildslave\unity\build\artifacts\generated\common\editor\BuildPipelineBindings.gen.cs:331)
UnityEditor.BuildPipeline:BuildPlayer(String[], String, String, BuildTargetGroup, BuildTarget, BuildOptions) (at C:\buildslave\unity\build\artifacts\generated\common\editor\BuildPipelineBindings.gen.cs:232)
UnityEditor.BuildPipeline:BuildPlayer(BuildPlayerOptions) (at C:\buildslave\unity\build\artifacts\generated\common\editor\BuildPipelineBindings.gen.cs:210)
UnityEditor.BuildPipeline:BuildPlayer(String[], String, BuildTarget, BuildOptions) (at C:\buildslave\unity\build\artifacts\generated\common\editor\BuildPipelineBindings.gen.cs:204)
BuildMenu:Build(BuildTarget, Boolean, Boolean, Boolean) (at Assets\URSE\Editor\BuildMenu.cs:338)
BuildMenu:BuildRunAndroid() (at Assets\URSE\Editor\BuildMenu.cs:42)

(Filename: Assets/URSE/Editor/BuildMenu.cs Line: 338)

Android PostProcess task "Processing resources" took 33.2232 ms
Android PostProcess task "Preparing APK resources" took 46.535 ms
Android PostProcess task "Process plugins" took 442.0586 ms
Android PostProcess task "Processing Android libraries" took 10.2794 ms
Android PostProcess task "Creating Android manifest" took 2939.9228 ms
Android PostProcess task "Compiling resources" took 16.7858 ms
Android PostProcess task "IL2CPP" took 0.7606 ms
Android PostProcess task "ZipIl2cppSymbols" took 0.6118 ms
Android PostProcess task "Preparing streaming assets" took 118.6001 ms
Android PostProcess task "fastzip" took 0.2408 ms
Android PostProcess task "AAPT: Compiling all assets into one archive" took 0.4608 ms

 

This is not related to the project or version of the Unity. Occurs as example in different projects in 5.5.4p5 and 2017.1.1p3. I'm doing a build through BuildPipeline.BuildPlayer for Android with gradle and sometimes a couple of times in a row build failed because "Could not create empty folder". But the next build without any changes ends successfully. On other machines the build this projects works without errors. I tried to clear the folder Temp\gradleOut before build, update Java, it does not help. I'm on Windows 10, other machines on Windows 7.

 

I made an empty project, copied plug-ins into it and made 50 builds in the loop. There is no error. Continue to investigate.

 

old screenshot:

full report:

main gradle:
https://hastebin.com/jejuyepuwi.sql
lib grade:
https://hastebin.com/urivupuday.php

 

I get this issue randomly as well when building with Gradle in 2017.2p1

Doesn't happen all the time, but enough to be annoying. Usually another rebuild will fix it. Its usually on different plugins that it fails on. I've had it on UTNotifications, UnityPurchasing, Heyzap... doesn't seem to be specific plugins.

 

This bug got fixed when I cleared the disk. My disk was almost full(enough space for the build though) but still was throwing the error. I deleted the unnecessary files and it worked!

 

How much disk space you have to clear? I have about 20GB free space (entire project has about 1GB max, final game is about 70MB) and still get these errors sometimes and have to manually delete gradle build folder inside Temp and rebuild.

 

i had the same error in unity 5.6.5f1.But the second export was successful.