Async CTP v3 – installation

The third version of the Async CTP was released on 31st October 2011.

The reason for releasing v3 is to address installation issues -- a recent Windows Update had conflicted with the Async CTP v2 and stopped it working, or prevented its installation in the first place. The v3 release also contains one small bugfix, to stop intermittent VB IDE crashes.

This post is to help with some common installation issues.

Run Windows Update before installing Async CTP v3, and get all updates (including Optional updates) from before October 2011

*** BUT NONE that came after. Three in particular, KB2635973 and KB2615527 and KB2645410, are known to be incompatible with Async CTP v3.

After installing Async CTP v3, then you can get subsequent updates.

Q. Why do we keep releasing updates of the Async CTP? This is the third version so far:

  • October 2010 – original Async CTP v1
  • April 2011 – Async CTP v2 (SP1 Refresh), to make it compatible with SP1 of VS2010 and fix some bugs
  • October 2011 – Async CTP v3, to make it work with recent product updates

The reason is that Visual Studio and .NET4 keep being updated. The Async CTP is actually a mini-fork of VS2010. Therefore, each time there’s a Windows Update which includes changes to the VB or C# compilers, then the Async CTP gets out of date: the update will break the Async CTP if you have it on your machine, and it’ll block the Async CTP from being installed on top of it. So far these conflicting updates have been coming out about once every six months, and so we’ve had to re-release the Async CTP every six months.

Note: The Async CTP v3 can be installed over the top of Async CTP v2 (SP1 Refresh): you don’t need to uninstall it first.



A quick check that the Async CTP is working

If you suspect that something’s wrong with your installation of the Async CTP, then please check the version number of these four files. (Please check all four, even if you’re not doing C# or VB or Phone development).

  1. C:\Windows\Microsoft.Net\Framework\v4.0.30319\csc.exe
  2. C:\Windows\Microsoft.Net\Framework\v4.0.30319\vbc.exe
  3. C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\msvbide.dll
  4. My Documents\Microsoft Visual Studio Async CTP\Samples\AsyncCtpLibrary_Phone.dll

If you see the following version numbers, then the Async CTP Refresh has been correctly installed:






Async CTP v3




Q. How to find those version numbers? A. Right-click on each file and choose Properties; the version number is in the "Details" tab.

If the version numbers are incorrect

Here are some other version numbers you might find











Async CTP v1





VS2010 SP1





Windows Update or
Async CTP v2
(SP1 Refresh)
4.0.30319.440 10.0.30319.440 10.0.40219.15

Async CTP v3




I want to stress this: you should check the version numbers of all four files. Even if you think you're not going to use C#, say, you should still check all four files including csc.exe. Any discrepancy in any of the files will indicate your machine is in an incorrect state.



If Visual Studio crashes upon opening a VB/C# project

The issue is that VS2010 SP1 had a bug in NGEN. The Async CTP v3 requires that this bug have already been fixed – either by having Async CTP v2 already on the machine, or by running Windows Update and getting all updates including optional ones, or by manually installing KB2468871.

Alternatively, if you’ve already got Async CTP v3 on your machine, you can fix the bug manually: open a Developer Command Prompt, run the following command in it, and have a nice cup of tea and biscuit because it’s going to take up to an hour:

ngen update /force



To uninstall Async CTP v3

This is easy: Start > ControlPanel > UninstallPrograms > ViewUpdates, search for all updates with “async” in their title, and uninstall all of them. You might see as many as five different entries that need to be uninstalled.

TIP: Although uninstall order doesn’t matter, it goes easier if you uninstall the “Visual Studio Async” updates first and the “.NET Framework Async” updates next. That’s because the uninstalling the latter will require a reboot.

To uninstall Async CTP v2 (SP1 Refresh)

The uninstall of Async CTP v2 has become broken due to a conflicting Windows Update. If you have v2 on your machine and want to install it, then you actually have to install v3 first.


To uninstall Async CTP v1 (pre-SP1 release)

If anyone still has Async CTP v1 from October 2010: we recommend to uninstall this prior to installing SP1.



If you still have problems

Please post a request for help in the Async Discussion Forums. We do monitor those forums frequently, and we may be able to help.

When you ask for help, PLEASE mention all four version numbers. That will help!

Comments (20)
  1. LarsM says:


    I installed all the new Silverlight 5 stuff into my VS SP! yesterday, and today tried to install the Async CTP v3 on top.

    Installer finished OK, but there is absolutely no trace of the CTP files anywhere, and async / await calls is not recognized by VS.

    Is this still a know issue, or have you sorted out the installer since early November.

    Please advice, I really do no want to reinstall my whole VS environment.


  2. James says:

    I have same problems as LarsM

    After install CTP-V3, any sample files can not be found. Please advice.

  3. Manju says:

    I too installed the Async CTP v3 todat but couldn't find any files.

  4. andre says:

    I can't find the files either

  5. LaughingJohn says:

    Same problem here. Seems to update ok but no files in "my documents". I originally tried to install over the V2 CTP, but couldn't find the silverlight 5 dll. I deleted that folder and reinstalled and now there is no folder at all (sigh).

  6. Tugberk says:

    Hi, I installed the ctp, everything is fine except for the samples.

    It is a little odd that you targeted a folder on installation which might not be there. Why did you do that?

    I am assuming that installation targets the folder %userprofile%My Documents and I do not have that. Windows comes with %userprofile%Documents.

    Is there any other standalone installer which I can only install samples and dlls?

  7. Anonymous says:

    WTH. Why is installing an executable so difficult? I don't have time to troubleshoot an executable from a multi-BILLION dollar company. Now I have to restart my computer. GREAT.

  8. Tyler says:

    Had two computers on my team install and no files. I noticed that when the install goes well, the readme launches at the end. When it does not, no readme is launched (yet no installation error).

  9. James says:

    Finally find the solution, make sure two things

    First, if you install Silverlight 5 Tools, uninstall it.

    Second, reset your folder "My Documents" to default location.

    than re-install Async CTP V3, you will find the samples. Hope it helpful.

  10. Problems with the Async CTP 3.0 installer says:


    It seems that the Async CTP 3.0 installer in…/details.aspx

    is not a full installer (is an update/refresh installer).

    See my Forum posts:…/580668a1-9002-4faa-bc64-e01f850fab5a…/fce894bd-ee7a-4007-b63c-9153fab82d9c

    How can I make a full installation ?



  11. Matt says:

    Guys, this is getting ridiculous. You ask people to test your product in beta. Neither the CTP 3 version installs correctly on top of VS2010 Professional plus SP1 nor does the VS11 Beta work with the CTP3 sample projects. I spent half a day trying to figure out how to solve this and have given up. The CTP3 Refresh installs correctly, I see the folders in MyDocuments directory. However, in the IDE the async keyword is NOT recognized. No, I do not run Resharper nor other tools. I virtually uninstalled EVERYTHING related to VS2010, did a clean install of VS2010, a fresh install of the SP1 and a fresh install of the CTP3 Refresh. IT DOES NOT WORK. Guys, I dont know whether I am the only one but I feel this is embarrassing. If a product cannot even be installed by programmers then I do not know what else to say. I think the hundreds of comments on various sites and blogs of users with the exact same issues SPEAKS VOLUMES. Can you guys somehow get your act together and get a solution that actually works? I am upset because I wasted a full day on this and I seriously do not think the problem lies on my end. The install has been a nightmare and I can only say "Microsoft". Please guys, prove me wrong, show me I am barking up the wrong tree……

  12. Matt says:

    btw, my msvbide.dll version shows as 10.0.40219.1, I have not the slightest clue how to get it updated to 4.0.40219.15. Is there anything that I am overlooking. I am just extremely frustrated because I need to use an Actor model concurrent framework that relies on the new async/await functionality and I have no clue how to even start working with the IDE not recognizing the new CTP functionality….

  13. @Matt: is it possible you have KB2645410 installed under ControlPanel>WindowsUpdate>ViewUpdateHistory? That results in the behavior you observed. The answer there is to uninstall it first, then install the asyncctp, then reinstall the KB.

    Otherwise: please email me ( with a list of all updates you have. Maybe I'll spot something else that conflicts.

    As for VS11Beta: it is expected that it won't work with CTP projects; all CTP projects will need to be updated, but the update is easy. (1) Change target framework to .NET45; (2) Remove the reference to AsyncCtpLibrary.dll; (3) change code to use "Task" instead of "TaskEx"; (4) we've removed SwitchTo() methods since they lead to bad patterns.

    Note: VS11Beta is not yet able to use async to target anything other than .NET45 or Metro. To target other frameworks it requires a compatibility library. We haven't yet released such compatibility libraries. David Grunwald made a preliminary version of one on github:

  14. The async setup is really horrible buggy. When I uninstalled Async the setup leave a mixture of Sp1 and Async files on my HDD which causes VS2010 to crash all the time. I had to uninstall the VS2010Sp1 and install Sp1 again. Now all files are back at Sp1 level and VS works again.

  15. Matt says:

    Lucian, thanks for the tips but your suggestion does not solve the problem, unfortunately. I uninstalled all KBs related to Visual Studio, uninstalled the SP1, uninstalled VS2010 itself, then installed the IDE and SP1 again and on top of it CTP3. The version name of msvbide.dll version shows as 10.0.40219.1. Another issue that I am having is that the csc.exe version shows as 4.0.30319.517. This may be because I installed the VS11 Beta, then uninstalled it again because I wanted to take another shot at a clean CTP3 install as pointed out above. Apparently the csc.exe was updated by the VS11 Beta. Not sure this plays a contributing factor to the issues I am having. If it does can you pls advice what to do to get ride of it. As described above I already reinstalled a complete version of VS2010 after I uninstalled the VS11 Beta.

    I am extremely keen on getting this to work otherwise I would not bother and simply wait for a production version of VS11.

    P.S.: As pointed out I have no KBs remaining that pertain to VS, only KBs relative to Windows.

  16. @Andre: what you describe is typically caused by uninstalling just one part of the AsyncCTP. It installs two or sometimes three entries in the AddRemovePrograms>ViewInstalledUpdates, and all of them have to be uninstalled.

  17. no, I removed all updates which have Async in Name.

  18. Eyal says:

    is  10.0.40219.355 as the file version of msvbide.dll should be OK ?

  19. Evgeni says:

    No directory My DocumentsMicrosoft Visual Studio Async CTP — can't find assembly AsynCtpLibrary.dll.

    Async CTP v3, VS 2010, Windows 7

  20. And I cn find ;( says:

    I too installed the Async CTP v3 todat but couldn't find any files.

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