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The Error "Copying assembly from Temp to Library failed" appears when updating the project to 2019.2.0a8 version



To reproduce:
1. Open attached project "prof"
2. Open it with Unity 2019.2.0a8
3. Close and reopen the project with 2018.2.0a8 and check the console

Actual result: error appears in the console
Expected result: there should be no error.

Reproduced with: 2019.2.0a8
Can't reproduce with 2019.2.0a7

Copying assembly from 'Temp/com.unity.multiplayer-hlapi.Runtime.dll' to 'Library/ScriptAssemblies/com.unity.multiplayer-hlapi.Runtime.dll' failed

  1. Resolution Note:

    Should be fixed in HLAPI package v 1.0.2

Comments (19)

  1. OctaLuna123

    Nov 16, 2020 14:35

    Hola Buenos días, yo uso la versión de Unity 2019.4.14f11; primero usaba una versión de Unity 2019.2.0f1, no tuve problemas hasta que cambie de posición mis proyectos, y me aparecía el error Copying assembly from 'Temp/Assembly-CSharp.dll' to 'Library/ScriptAssemblies/Assembly-CSharp.dll' failed, busque como solucionarlo primero reimporte los Sprites y Scripts, y me función pero cada cierto momento me aparecía el error y me molestaba, luego seguí buscando en Internet mi error y la otra opción era que tenia un malware y examine mi equipo con malwarebytes y no tenia ningún malware luego use Eset para examinar mi equipo y no tenia nada, luego pensé que era por la versión de Unity que tenia y me actualice a la vercion 2019.2.0f1 y no tuve problemas hasta que programe un Script y me apareció nuevamente el problema, reimporte de nuevo pero no funciono y no puedo trabajar con ese error por que no se va.
    Me encanta programar en unity y es mi programa favorito para crear juegos pero me encontré con este problema y quisiera que me pudieran ayudar

  2. UDN_e7666fec-2cb5-4cfe-a678-e5e5ba6ec4ce

    May 16, 2020 00:40

    Turn off your antivirus software,Not realizing it caused me a lot of trouble.

  3. Yo030

    May 15, 2020 04:08

    Unity 2019.1.7.f1
    I think I may have found the solution, although I am not sure what it was, but this is what I did:
    I went to Window > Package Manager
    I installed Multiplayer HLAPI
    installed XR Legacy Input Helpers (The one that caused me this error)
    Removed XR Legacy Input Helpers
    installed XR Legacy Input Helpers (Yes, I did this twice)
    Removed XR Legacy Input Helpers
    I opened Android Studio and installed API 23 & 24, after it was complete, I went back to Unity
    I reinstalled XR Legacy Input Helpers
    And the error was gone. Hope it helps someone.

  4. alstovbur

    Apr 17, 2020 18:21

    Actual for 2019.3.10f1

  5. Marcos-Elias

    Mar 30, 2020 14:15

    Happened here in 2019.3... after upgrading the Post Processing effects package.

    Removing that multiplayer package solved it, I don't know why. It’s unbelievable how unstable Unity became, lots of hours lost each update... Seems a random problem with the package manager.

  6. aerospacevitd

    Nov 26, 2019 15:37

    This issue continues to persist and none of the suggested fixes work for us.

  7. Dami-Juana

    Oct 21, 2019 13:36

    I had the same error,
    Update the multiplayer package worked for me on 2019.2.5

  8. dienat

    Oct 18, 2019 22:49

    Same error , i get these using 2018.3:
    Copying assembly from 'Temp/Obi.dll' to 'Library/ScriptAssemblies/Obi.dll' failed
    Copying assembly from 'Temp/Unity.Postprocessing.Runtime.dll' to 'Library/ScriptAssemblies/Unity.Postprocessing.Runtime.dll' failed
    Copying assembly from 'Temp/Unity.TextMeshPro.dll' to 'Library/ScriptAssemblies/Unity.TextMeshPro.dll' failed

  9. casoich-DDI

    Oct 08, 2019 16:43

    I'm going to comment this here, because I _THINK_ I found the culprit/fix. At least, it's still working for me...

    I went into `Preferences->External Tools` and increased `Maximum JVM Heap Size, MBytes` from 4096 to 6000.

    I'll report back if it's not actually a fix, and hopefully others will try it and report too.

  10. mccann

    Sep 30, 2019 14:39

    Issue happened on 2019.2.5f1. I removed the multiplayer package (wasn't using) and resolved the issue.

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