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Error about SIPEPS DLL with UCMA 4.0

Posted: August 21st, 2012 | Author: | Filed under: UCMA 4.0 | Tags: , , | 10 Comments »

One of the first issues you may run into when trying out the new version of UCMA is an exception that says a DLL called SIPEPS, Version= could not be found. This happened to me, and a few other people I’ve spoken to had this problem as well. So, to help anyone else who gets this exception, here are a few troubleshooting steps that should fix it.

The exception can be very bewildering because UCMA projects don’t require an explicit reference to this SIPEPS DLL, and often you’ll get the exception even if you locate the DLL and move it into the same directory as your application. It turns out that it’s usually caused by one of two things:

  1. You’ve targeted the wrong version of the .NET Framework.
  2. You’ve targeted the wrong type of CPU.

So, before getting too frustrated, open up the properties for your project in Visual Studio 2012 and make sure .NET Framework 4.5 is selected. (If you’re not running Visual Studio 2012, you have a somewhat larger problem, because you can’t use .NET 4.5 with Visual Studio 2010 and earlier.) If you had an earlier version of the framework selected, change it, rebuild the project, and try again. UCMA 4.0 lists .NET 4.5 as a requirement.

If you’re still getting the exception, check the target platform and make sure it is Any CPU or x64 for all projects. UCMA has only worked on 64-bit machines since the 3.0 version, and what sometimes happens is that a project will get inadvertently set to x86, and will therefore try to load a 32-bit version of SIPEPS.dll on startup. Well, there isn’t a 32-bit version of SIPEPS.dll; hence the somewhat misleading exception.

If neither of these steps solves your problem and you’re still getting the exception about SIPEPS, definitely let me know by posting a comment here and I’ll do my best to help.

10 Comments on “Error about SIPEPS DLL with UCMA 4.0”

  1. 1 Mafyou said at 6:19 am on September 6th, 2012:


    In fact, when you want to create a web site using UCMA 4.0, you can’t because of SIPEPS 5.0 runing only in x64.
    To solve this, you should go throught a WCF service.

    Thanks your blog btw.

  2. 2 Csaba Vegso said at 9:32 pm on October 27th, 2012:

    Hi Michael,

    UCMA 4.0 SDK (Preview) download page lists Microsoft Visual Studio 2010 SP1 as the required development environment and .Net Framework 4.5 as the required runtime. However, Microsoft Visual Studio 2010 SP1 does not allow selecting .Net Framework 4.5 as Target framework (it supports up to 4.0). I am getting really confused ….

    I also tried to install UCMA 4.0 (Preview) SDK for Visual Studio 2012 Premium Edition and .Net Framework 4.5 but UCMA 4.0 SDK installer stops at the last step of the installation procedure (while installing Core Components). I know that a lot of guys are already working with UCMA 4.0 SDK. I just want to know the place where I can download those UCMA 4.0 SDK bits which supports Visual Studio 2012 and .Net Framework 4.5.

    Thanks in advance

  3. 3 Csaba Vegso said at 5:50 am on October 29th, 2012:

    Forget about it. Installing .Net Framework 4.5 -> VS2010 -> UCMA 4.0 SDK (Preview) ->VS2012 Premium on my Windows Server 2008 R2 box works. It is really painful but works.

  4. 4 Michael said at 10:28 am on October 29th, 2012:

    Glad to hear you got it working. I’m not sure why VS 2010 SP1 is listed as a requirement – I’ve been using VS 2012 with no problems although it looks like I did have VS 2010 previously installed. I’ll see if I can find out what’s going on.

  5. 5 Arunas Ruksnaitis said at 6:48 am on January 24th, 2014:

    Hi Michael,
    Very useful this site of yours.
    Since you are asking…I am still getting this error in my project, but only when I am trying to add “Replaces” header to my CallEstablishOptions.
    The project compiles and works perfectly well until I try to use Microsoft.Rtc.Signaling.SignallingHeader (which confirms that the project settings are OK for UCMA). At this point both Intelisense and the builder complain “IClientTransaction unavailable; you must add reference to SIPEPS”
    Does it have anything to do with the fact that I am using FSharp Async to work with UCMA?

  6. 6 Furier said at 5:12 am on April 24th, 2014:


    All my projects are set to .NET 4.5 in the projects properties application tap, and on the build tab platform target is set to Any CPU.

    I’m using Visual Studio 2013, so all should be good there…
    In the build configuration manager iv tested with both Any CPU and x64 as active solution platform, and for the projects including UCMA 4.0 iv set the platform to x64 for the x64 configurations.

    I am still getting this annoying error. :S

    Exception is: FileNotFoundException – Could not load file or assembly ‘SIPEPS, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35’ or one of its dependencies. The system cannot find the file specified.

  7. 7 Kris W said at 9:22 pm on October 27th, 2014:

    Unfortunately it didn’t work for me: VS2013, UCMA 4.0. Runs wonderful on my local machine but fails while publishig: Framework set up to 4.5, platform target to x64 and yet still the same SIPEPS.dll missing dependencies. When I’ve previewed the exe file with dependency checker, it says that its missing IESHIMS.DLL, MSCOREE.DLL and OLE32.DLL

  8. 8 Kris W said at 11:30 pm on October 27th, 2014:

    OK, I’ve found that the issue was with the deployment server (2008 R2) :/

  9. 9 JKW said at 7:28 am on July 6th, 2015:

    Hello Michael,

    Thanks a lot!
    Setting the platform target from ‘Any’ to ‘x64’ worked for me!
    – Target .NET version: 4.5.2
    – Visual Studio 2015 RC
    – UCMA 4.0 SDK
    – Windows 8.1 x64

  10. 10 Dylan T said at 4:40 pm on January 4th, 2016:

    I found that in addition to setting the “Any CPU” setting, I had to ensure that the checkbox “Prefer 32-bit” was unchecked. This is a few lines below the CPU choice in the Build options.

    By default, with a console application, this box is checked.

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