[SOLVED] Copying assembly 'Temp/Assembly-CSharp.dll' failed

When I make changes to a script in mono develop and then switch to Unity very often this error is shown in the console and I am unable to run the project in the Unity editor.

Copying assembly from 'Temp/Assembly-CSharp.dll' to 'Library/ScriptAssemblies/Assembly-CSharp.dll' failed

I'm on version 2018.2.6f1 but I also had this problem on the previous version. This only started happening recently. I've read of other people having this issue. Closing Unity and reopening seems to work but as the error happens very often this isn't ideal.

Any advice on how to fix this is appreciated. Thanks.

 

Edit: It was just Kaspersky screwing things up.

 

Thanks, I also use Kaspersky. I've now added my project file as an exclusion in Kaspersky.

 

Can confirm this was caused by Kaspersky. After setting project folder to be excluded I have had no more problems.

 

Hey guys, I do not have Kasperskiy, instead the basic windows Defender. The issue is happening all the way, every 5 minutes. Any other ideas??

 

Try adding your project folder as an exclusion - link

 

mine error is still their , what to do guys?

 

Reimport you script file, can fix !

 

@jzzja ... If I had a penny... for every time I needed to close up and open it up my unity projects... ladies... I would be reach. But yes this time it worked

Copying assembly from 'Temp/Assembly-CSharp.dll' to 'Library/ScriptAssemblies/Assembly-CSharp.dll' failed

of course after I troubleshoot it for a little while!

thanks

 

The only solution seems to be right-clicking on the script folder and then left clicking on the Reimport menu item.

 

[QUOTE = "syedhasan1964, post : 3906463, member : 2007793"] 유일한 해결책은 스크립트 폴더를 마우스 오른쪽 버튼으로 클릭 한 다음 Reimport 메뉴 항목을 왼쪽 클릭하는 것입니다. [/ QUOTE]
해결됬습니다~ 정말 감사드립니다^^

 

I restarted Unity and it worked.

 

Yes: restarting Unity works. But this is must be an active bug. Nothing to do with Kaspersky. I get this 5 times daily. V. annoying!

 

The same problem 2018.2.13

 

yep this is the most annoying error - I get this multiple times a day and most frustrating of all after spending an hour waiting for a build it pops out and ruins the build. Usually on the postprocessing.dll.
Unity 2018.3.4

 

Yep, I also get this daily

 

Its the first time i get this.
and in unity i dont have the fille assembly-csharp.dll

 

This is annoying, the best/fastest solution I've found is to right click any script and re-import it. That way you don't need to reload everything or restart Unity.

 

This is NOT solved. Asking users to click import again and again isn't an ideal solution imho...

Same problem is being discussed here:
https://forum.unity.com/threads/cop...dll-to-library-failed-project-stucked.669616/

 

, remove the file
Library/ScriptAssemblies/com.unity.multiplayer-hlapi.Runtime.dll
and now build works again, once only. The file-removal procedure has to be repeated for every build

 

Thanks! Helped a ton!

 

I saw somewhere on forum that coin miner malware is causing this issue, tried to scan my pc, found 2 miners, deleted them and Unity started working again. I used malwarebytes.

 

Not fixed. Happening in 2019.2 and I'm not running any of those security programs.

 

This bug in conjunction with an issue that only lets me boot unity if i do it right after a fresh windows reboot....

 

FINALLY. I got a lot of Unity errors and this was the cause. Also solved with Malwarebytes. Looks like miners F*** up with the Unity importer... Thanks a lot, I've been having troubles for weeks.

 

I have a question is that active bugs can effect to my project ?, i dont know how to fix the code from the libary download. When i running game, everything just fine.
So just leave it be ?

 

껏다 키면 됩니다.

 

I've all of the solutions mentioned Above and none seems to solve my problem

 

same problem - repeatedly.
it may be that the file : /ScriptAssemblies/Assembly-CSharp-firstpass.dll' is still open (or again) in the unity editor when it tries to overwrite it as it compiles.

usually it looks like the whole directory is deleted and rebuild with the files as unity compiles the project.
When the error comes up, the file cannot be deleted, ansd therefore also the directory.

so far this time worked for me :
i reopened unity.
then deleted the file.
unity then complains twice within compilation that it can't create the directory (scriptassemblies) and asks to try again, which works.

so instead of having to reopen the project every 5 minutes i now just have to press a button twice.

seems like there is no failsafe and retry in the copy process of the temporary files, but there is one as it creates the directory.

really didn't dive into this, buit the above worked for me.

 

same here .... last solution worked temporary ....
This error is a huge waste of time.

 

I've deleted the Library and Temp folder, now the whole project doens't even start anymore!

 

Same problem

 

I've got the same problem here...

 

None of this fixes are working for us. We've removed almost all the packages and aren't using malwarebytes.

 

same problem with 2019.2.14f1

 

Holy cow, I could not believe, but this was it for me! I tried tried everything, I was on the verge of tears and Windows reinstall when I tried this out of desperation (I don't trust software I don't know). Malwarebyte actually worked, what surprised me the most is that the free version was enough. I had some 'TrojanBitCoinMiner' malwares...
THANK YOU!!

 

Thank You, this solution works perfectly!

 

Jesus.... Thanks a lot, this resolve my problem, I scan my pc with Malwerebytes and it found 7 that Coin miner, now that I remove the problem is fixed. Thanks a lot

 

Thanks worked for me

 

Wierdly enough that turned out to be true. Malewarebytes found the miner and problem was resoleved after the quarantine.

 

I'm having this same issue, but Malwarebytes found nothing on my computer. I then uninstalled Malwarebytes and still had the problem.

Then I did a fresh, clean install of Unity. I even cleared out all folders and also my Registry of anything dealing with Unity and still have that error.

I even started a new, clean project and the second the window opened, those two errors appeared.

So what is causing this problem seems to be totally random, as are the solutions.

 

For me the problem turned out to be caused by Dropbox, which I had syncing the project folder. Turns out that's a no-no.

 

Thank you very much! Malwarebytes resolved the issue.

 

Was just going to post this! Can't believe how many months this has been happening to me intermittently and finally noticed the syncing correlation. So frustrating and so glad it's fixed! Just click on the Dropbox icon and Pause Syncing.

 

Hey guys, same error here! It just popped out of nowhere, now I can't even start a new project. Got this issue for the first time after many many years.

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

Copying assembly from 'Temp/UnityEngine.UI.dll' to 'Library/ScriptAssemblies/UnityEngine.UI.dll' failed

I always get these two errors when I import something to the completely blank project. I also tried to clean my pc with antivirus, but nothing happened. I do not use any sync software as mentioned above, so it looks like something is missing or some files might be locked as there is stated it can't copy assembly files from temp to ScriptAssemblies? Any solution? Thanks!

 

Same problem (2019.3.7f1)... I have tried reinstalling Enigne = didn't work; than reinstalling Hub = didn't work;
No antivirus problem and even other versions of unity engine 2020 beta and 2018 don't work.

 

Hey guys, got responded from clever guy here and it helped me to figure out the issue!
Hope that helps too!
https://answers.unity.com/questions...rdll.html?childToView=1712468#comment-1712468

 

followed the same "solution" as what "clever guy" described and i'm not seeing an "auto key" script in there.
i'm not sure what's actually causing errors like these to pop up on my end, maybe i need to investigate more of this.

--- (Update 1) ---

the "general security" software (with all text of it written in Simplified Chinese i think, so it's Chinese software basically) was on all the time and was blocking Unity's access to copy one file to the other. which is why these errors suddenly disappeared on my end.

i have no hard feeling against such software but i had the software simply quit running in a normal way. (i couldn't understand Chinese) i can't really explain how i did it, it's a long story but what i will say is it's not that complicated and does not require Task Manager.

 

I had the same problem. Tried everything. Finally, I checked PC by Malwarebytes, it found 4 miners and a problem was fixed!

 

I just had the same error today!!!! on the new unity version!