Getting "copying assembly from temp folder to library script assemblies failed". Tried everything, nothing works.

Questions & Answers
1

Console:

Copying assembly from ‘Temp/Unity.TextMeshPro.dll’ to ‘Library/ScriptAssemblies/Unity.TextMeshPro.dll’ failed

Copying assembly from ‘Temp/UnityEngine.TestRunner.dll’ to ‘Library/ScriptAssemblies/UnityEngine.TestRunner.dll’ failed

Tried everything. Reinstall Unity Hub & Unity, nothing. Started a new project, nothing. Every since I update from 2018.3 version, I have got this message and dosen’t allow me to play the game (Editor).

I don’t have any anti-virus program, only Windows Defender (which it shouldn’t be any problem). I have delete all Unity files in AppData. Spent a whole week, to figure this, I need help now.

2

I do have the same problem. I tried everything I can find about fixing those bug but still no success.
After installing Unity Hub and Unity 2019.1.4 I get this error:

Copying assembly from 'Temp/Unity.TextMeshPro.dll' to 'Library/ScriptAssemblies/Unity.TextMeshPro.dll' failed

if I try to reimport all scripts, I get even more errors:
` Copying assembly from 'Temp/Unity.Analytics.DataPrivacy.dll' to 'Library/ScriptAssemblies/Unity.Analytics.DataPrivacy.dll' failed Copying assembly from 'Temp/Unity.CollabProxy.Editor.dll' to 'Library/ScriptAssemblies/Unity.CollabProxy.Editor.dll' failed Copying assembly from 'Temp/Unity.PackageManagerUI.Editor.dll' to 'Library/ScriptAssemblies/Unity.PackageManagerUI.Editor.dll' failed Copying assembly from 'Temp/Unity.TextMeshPro.dll' to 'Library/ScriptAssemblies/Unity.TextMeshPro.dll' failed Copying assembly from 'Temp/Unity.Timeline.dll' to 'Library/ScriptAssemblies/Unity.Timeline.dll' failed `
I do not have any antivirus-software or firewalls running (removed them for testing this).

Any help would be greatly appreciated.

3

I had the same issue. Tried the same things you did. What fixed my issue made no sense to me. So I had read that if you had malwares or some weird hidden virus it could prompt random errors in unity. I refused to believe it until I ran Malwarebytes. I had a few hidden bitcoin mining bots installed on mine(Wasn’t aware of this). After cleaning everything worked. Package manager was back in the windows tab and that textmeshpro error was gone. I couldn’t believe it