Visual Studio Tools for Unity not showing Unity instances

I'm running VS 2017 and any time I try to debug with multiple instances of Unity running, I am unable to connect the debugger. The "Select Unity Instance" dialog pops up, but doesn't list any of the running instances of Unity. If I close all other Unity instances it will connect to the single instance and the debugger works normally.

Associated tool versions:
VS 2017: 15.9.16
VSTU: (the change log lists as the newest but Visual studio has no available updates)
Unity 2019.2.8f1 (also happens with all other versions of 2019 that I tried)

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Bump. Am I the only one who has ran into this situation? I'm starting to wonder if there's something amiss with my dev environment.

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For what it's worth, I've been encountering this too. Visual Studio Community 2017 and Unity 2019.2.0f1. I'm running both Unity instances from the same project via sym-links (uEcho tool) for doing multiplayer development.

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I brought this up on the MS Visual Studio forums, and it basically boils down to a known issue that won't be fixed in VSTU for VS 2017.


many swearwords.

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So i really need to upgrade to 2019, so much work to reinstall all plugins and setup all working environments again...

did you try allowing the unity editor and visual studio via the Windows Firewall settings?
worked for me

This thread is well over a year old, turned out to be a known issue, and isn’t an issue with newer Unity or VS versions. Might I advise reading the entire thread and check the dates before replying?

Could you tell what the solution was? (of course, if you still remember) I have the same issue.

If you look at my earlier reply, specifically the link to the MS forums, that explains the issue. Sadly there wasn't any resolution for VS 2017. The only way around it was to upgrade to VS 2019. Since then, the way Unity integrates with VS has changed as well. I don't recall which version of Unity in which this was first supported, but there's also a package you can download within Unity that enhances VS support.

But that reply was incorrect. Visual Studio 2017 debugging has not been broken since Unity 2019. I'm not surprised Microsoft said the solution would be to give them $600 to upgrade to a newer version of their software :)

Ah, that’s a pity, thank you anyway)

My VS 2017 worked pretty well in Unity 2019, the problem started with 2020.3.16f1

Not that it is all that helpful but, this also only started for me when I upgraded from 2019.4.26f1 to 2020.3.18f1, and before that VS2017 worked just fine.

same upgrade path for me (like vdogamr): I upgraded Unity from 2019.4.32f to 2020.3.22f1 and before that VS2017 could find unity instance easily. Now VS can't find Unity any more.

So for Unity 2020 I need to upgrade to VS 2019 or later, to have the plugin work?

Hopefully Unity 2020 will also launch 2019 for the when opening the C# within it, and the ongoing game in Unity 2018 with VS 2017 will keep doing it also, or things will get very complicated for any dev with multiple projects on their plate...

I have the exact same issue with Unity 2020.3.9f1 and VS 2017: the "Attach to Unity" button won't find any Unity instances.

Strangely enough, selecting Attach Unity Debugger from the Debug menu works just fine for me. Give it a try.



Genius! that fixed it for me!

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I loaded VS 1st and then unity and that seemed to solve this issue for me, thanks for the help :)

Strangely enough, it’s also work for me. Thank you.

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