Weird error: Microsoft (R) Visual C# Compiler version 3.5.0-dev-20359-01 (8da8ba0c)

Question

I have a Unity 2020.3.22f1 project that was perfectly working at first. However, this error occured after editing and saving one of my scripts in Visual Studio (with no apparent bug in it):

I don't give details about my script or the project, because it doesn't seem to relate to the project itself or what I did, as the error appears now in all my Unity projects! I first tried to delete the script that triggered the bug, then I deleted the whole project. I even uninstalled/reinstalled Unity (different versions), Visual Studio and Unity Hub. But it seems that now I'm stuck with this forever.

Does anyone have a single clue about this? I saw one or two people having the same problem on the web, and with no other solution than formatting the hard drive. As I'm not working on my personal computer, I can't do that...I mean, there must be a rational explanation to this bug!!

I downloaded the latest version of Unity (2021.2.2f1), launched a brand new project, and the error now turned to: "The specified path can't be found" (rough translation from french), without more precision...still no idea what it means.

What you show there does not appear to be an error, just a version statement. Please post the actual, complete message that you get - even if it's in French. — 500 - Internal Server Error, Nov 12 '21 at 12:42
Thank you for your response! The complete message is exactly what I posted (here in french): "Le chemin d'accès spécifié est introuvable"...and that's it. I can add an image to clarify this in my message. — jules, Nov 12 '21 at 12:53
There must be some invalid file reference. Please post a repro. — 500 - Internal Server Error, Nov 12 '21 at 12:59
Thank you again. I added a screenshot to the original message. — jules, Nov 12 '21 at 13:01

score 1 · Accepted Answer · answered Nov 18 '21 at 14:24

Ok, I found a solution from here: Unity 2019.3.0a7: Microsoft Visual C# Compiler Errors

I don't know how it's related, but it is suggested that the error can be triggered by uninstalling Anaconda and Python (which I happened to do recently), which leads to remaining artifacts in the Windows registry. I then deleted the following item in the Windows registry:

Computer\HKEY_CURRENT_USER\Software\Microsoft\Command Processor\AutoRun

and restarted Unity. Now it works!

score 0 · Answer 2 · answered Nov 17 '21 at 13:24

Got the same issue, the problem is in an incomplete path

Command line is : "C:\Program Files\Unity\Hub\Editor\2022.1.0a13\Editor\Data\Tools\netcorerun\netcorerun.exe" "C:/Program Files/Unity/Hub/Editor/2022.1.0a13/Editor/Data/Tools/ScriptUpdater/ApiUpdater.MovedFromExtractor.exe" "Library\Bee\artifacts\mvdfrm\UnityEngine.LocalizationModule.dll_9374ECE80455BEFE.mvfrm" "C:\Program Files\Unity\Hub\Editor\2022.1.0a13\Editor\Data\Managed\UnityEngine\UnityEngine.LocalizationModule.dll" Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.IO.DirectoryNotFoundException: Could not find a part of the path 'C:\Users\damos\project name is missing here\Library\Bee\artifacts\mvdfrm\UnityEngine.LocalizationModule.dll_9374ECE80455BEFE.mvfrm'.

This path is missing the project name between damos ans library

As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). — Community, Nov 17 '21 at 14:53
Many thanks for your response! If I get it correctly, you say that the name of my project is missing in a path, but I don't understand what path you are talking about, and what is exactly the "command line". Sorry about that. Could you be more specific? — jules, Nov 18 '21 at 14:13

Weird error: Microsoft (R) Visual C# Compiler version 3.5.0-dev-20359-01 (8da8ba0c)

2 Answers2