SlowCheetah - XML Transforms


This package enables you to transform your app.config or any other XML file based on the build configuration. It also adds additional tooling to help you create XML transforms.. Written by: Sayed Ibrahim Hashimi, Chuck England and Bill Hiebert

(103) Review
Visual Studio
2013, 2012, 2010
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by CloudKarthik | Tue 8:54 AM

SlowCheetah doesn't work with Windows azure Web/worker Role projects.

by maskey | April 17 2014

by Mathias Colpaert | April 01 2014

SlowCheetah might be a bit buggy to set up, but once it works its great!

by Micky D | March 28 2014

Conflicts with ReSharper 8.1. Had to Suspend and Resume Resharper because I could not edit any file after applying a template

by Craig Brett (JP) | March 25 2014

I spent an afternoon trying to get this going for a team project. After a fair while thrashing with the already-mentioned "The SlowCheetah.Xdt.TransformXml" task could not be loaded from the assembly" problem, I eventually solved it by deleting the %localappdata%\Microsoft\MsBuild\Slowcheetah folder and it semed to resolve itself on my local machine and I was allowed to build and run stuff. I then deployed this to my colleagues who didn't have the plugin, under the impression that the NuGet package would make everything alright. No joy, regardless of what I tried. I'm now having to see if I can hand-roll a solution for changing config settings for people. Gets 2 stars because I like the idea and it kind of worked on my machine.

by Daniel Castenholz | February 07 2014

Nice integration with VS. Makes a chore much more manageable.

by Spesimensen | January 30 2014

Excelent tool! Thank you very much.

by Leonidas1 | December 06 2013

by AranV | November 27 2013

by 2Toad | November 23 2013

An invaluable addition to Visual Studio! Totally beats editing project files by hand. Well done!

by schleeke | November 11 2013

by Eric A. Duesing | November 01 2013

by Christoffer Johnsson | November 01 2013

Very nice tool, keep up the good work.

FYI to all people that get's build errors and use Ncrunch. You must include the package in Ncrunch, else you will get build errors.

Version works well with ncrunch, version and doesn't.

by ankgupta067 | November 01 2013

facing error -
Error 1 The "SlowCheetah.Xdt.TransformXml" task could not be loaded from the assembly C:\Users\SESA254846\AppData\Local\Microsoft\MSBuild\SlowCheetah\v2.5.10\SlowCheetah.Xdt.dll. Could not load file or assembly 'file:///C:\Users\SESA254846\AppData\Local\Microsoft\MSBuild\SlowCheetah\v2.5.10\SlowCheetah.Xdt.dll' or one of its dependencies. The system cannot find the file specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. ConsoleApplication2

by WorkAByte | October 22 2013

amazing, cant believe I haven't found this sooner!
thanks for the simply awesome plug in

by MToons | October 08 2013

Excellent work -- so far only one major problem with web applications (solved here:

by e.sabbadin | September 19 2013

It works in vsnet 2012, but NOT on the TFS build server. I did not installed the plugin on the built server
I expected that the plugin was required only in the configuration phase, not to trigger the magic
, that is that it used the native xmltrasform features .. isn0t it the case ?

Sayed-Ibrahim-Hashimi September 21 2013
| Edit |

Hi e.sabbadin, when you install SlowCheetah into a project there is a message in the package manager console regarding build server support. Because of the way NuGet package restore is implemented there is some additional steps that need to be taken. You can read more info on how to enable that at

by Ed Schimmel | September 13 2013

It really annoys me that after an upgrade Slow Cheetah suddenly stopped working. In the first instance I was really pleased with this tool, but I can not use it when it is this buggy. It is a shame that there are no other tools doing the transformations, as far as I know.

Sayed-Ibrahim-Hashimi September 14 2013
| Edit |

Did you file a question in Q&A regarding your issue?

FYI please don't expect each release to be bug free. This is a one man project so I rely on the community to help in reporting issues when they arise.

by Mohammad Azis Fatoni | September 13 2013

by Pbsharper | September 06 2013

Highly recommended!
Used it for polyglot (f# c#) project. Worked without a hitch!

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  • How to transform files For DEBUGGING in web projects
    1 Posts | Last post April 25, 2013
    • In the description of your tool it is said 
      "When you build your applicatoin the files are transformed and dropped into the output directory. "
      "For web projects the files are transformed ONLY when you publish or package your application."
      How can I invoked the transformation to debug web project without publish?
      I've asked the question on, but haven't get a good suggestion.
  • ClickOnce problem
    2 Posts | Last post April 24, 2013
    • Hi,
      i have a Wpf-project with SlowCheetah on board. The project include a folder with the settings.config file. It's an XML-file with different settings. I added a transform to it for the Release configuration. And it work when i build the project. With Debug build i have one config, and with release build i Have another. So far so good. But when i publish the project i always get Debug config. Can you help me?
      Some details: VS2012, SlowCheetah 2.5.5, the settings.config has Build Action=Content, and it is always copied into output. 
      There is a sample project to illustrate the problem but i don;t know how to attach it.
    • I'm not really shure what i've done but transformations don't work at all in the test project now. Nither on build nor on publish.
  • Exclude transformations from sourcecontrol
    1 Posts | Last post April 08, 2013
    • Hi, I'd like to exclude certain transformation files from source control because they contain sensitive info. I noticed I have the option to exlude the app.config file, but not the "subfiles" created by this extension. How can I make sure the sensitive info doesn't make it's way to source control?
  • Set up my app.config and check in code properly
    1 Posts | Last post April 01, 2013
    • Hello, I have a hard time to set up app.config, app.debug.config and app.release.config in my console application.
      If in the local app.config there is “<add key="ServiceID" value="R2" />”. And in the server it should be 
      <add key="ServiceID" value="R1" />. 
      I can’t use “R1” in mylocal machine to debug, otherwise an exception is thrown out.
      I did add <appSettings xdt:Transform="Replace"> in the app.release.config.
      Then the value is “R1” in app.release.config and it is “R2” in app.debug.config. Is it right?
      My questions:
      1) What is the value in app.config? "R1" or "R2"? I need a direct answer.
      2) When I check in the code app.config, What is the value in app.config?
      A little explaination is appreciated.
  • Original Config file modified
    12 Posts | Last post March 25, 2013
    • Hi,
      I have just installed and am using Slow-Cheetah.  I am using it to transform my Log.config which is used by Log4Net.  It is modifying the original config file, and not just the config file in the output directory.  This means that if if have an 'Insert' transform and build 3 times, I will get the XML element inserted 3 times into the original file.
      Can you confirm this bug?
    • FYI - I'm using Slow Cheetah version 2.5.5 and VS2010 SP1.
    • I've heard of this but I've been unable to repro it. Does this happen for new projects as well? If so could you give me some repro steps? If its only on a specific project can you share the project?
    • Hi Sayed,
      I've reproduced this with a bare bones project.  It is an Empty Web Application and I am running the transforms on Log.config.  You can see that if you build the app multiple times, the original Log.config file has the XML inserted every time.
      The I am using VS2010 Ultimate SP1.
    • Thanks for sharing the project. When I extract this and run the app the source config file is not changed at all. I'm not sure what's going on here. What OS are you running? I have win 8 here.
      One thing that might help here is to share a build log with me. For the project you shared, can you try the following. In VS go to Tools->Options->Projects and Solutions->Build and Run, set MSBuild output verbosity to Diagnostic. Kick off a build which causes the file to get modified. Copy and paste the build log from the output window. If you could email that to me at I can compare it to that of my machine and see what the difference is here.
    • I think this is the same error I've mentioned above. It's attempting to write over the original source file: Could not write Destination file: Access to the path '***originalfilepath***' is denied. Windows 7 Professional, VS 2010.
    • I have a team member that is experiencing the issue while I am not being impacted.  We both have pretty identical desktop images, however our VS installs are different (he has Pro 2010 while I have both Ult 2010 and Prem 2012).  I'll get diagnostic traces from both his and my version of the same project and send them to you as well.
    • I've noticed if I right click on the project and select 'Publish' it errors, if I use Build > Deploy through VS toolbar it works successfully. Not sure what the difference is. Just a quick note.
    • Outside of the obvious entire solution build vs single project.
    • My colleague and I have downloaded the repro project and have verified that his environment is affected while mine is not. Both he and I ran builds with diagnostic output enabled and the one main thing I see is that in my log (which is transforming correctly) I see the following:
            OriginalItemSpec = C:\Users\\Downloads\SlowCheetah\SlowCheetah\SlowCheetah\bin\**\*.*
      The above lines are *not* present in my colleague's build log.  I'll email you both logs in their entirety for you to investigate.
    • What I found is that the Targets file may be incorrect.  I'm running Visual Studio 2010 Premium.  Here's what I was getting:
      6>Task "SlowCheetah.Xdt.TransformXml" (TaskId:286)
      6>  Transfroming source file: X:\**********************\Data\DataModelClient\ServerURLConfig.xml (TaskId:286)
      6>  Applying Transform File: ServerURLConfig.Debug.xml (TaskId:286)
      6>  Output File: bin\Debug\ServerURLConfig.xml (TaskId:286)
      6>X:\**********************\packages\SlowCheetah.2.5.5\tools\SlowCheetah.Transforms.targets(101,5): error : Could not write Destination file: Access to the path 'X:\**********************\Data\DataModelClient\ServerURLConfig.xml' is denied.
      6>Done executing task "SlowCheetah.Xdt.TransformXml" -- FAILED. (TaskId:286)
      When I change the Destination attribute on the task as follows, it works properly:
    • Two things that I should have made note of: the transform was failing before because the XML file was read-only.  The second is that referencing projects are copying the non-transformed XML into the bin directories.  That may be an unrelated item, but is a result of the fact that the XML file is being transformed in the referenced projects bin folder instead of the XML source location.
  • app.Release.config & app.Debug.config not appearing in solution list
    2 Posts | Last post March 23, 2013
    • G'day,
      Just installed SlowCheetah, love the concept.  But I've run into a bit of a problem: after adding a transform, the files app.Release.config & app.Debug.config appear in the directory, but not in the solution list within visual studio (2010).  That is, while app.config is there, no "+" is next to it, nor are the other two files shown anywhere.  Any clue what I'm doing wrong?  Or is this a known bug?  I've tried creating a blank visual basic project, added in an app.config file, transformed it, and got the same result.
      Thank you,
    • Thanks for the note. I'm not following you, could you give a step by step describing the issue?
  • Preview transformation strips out spaces
    2 Posts | Last post March 23, 2013
    • Hi all,
      I have a web.config and some transformations for it. whenever i try to preview a transformation (great feature!) i see lots of changes. This is mainly because SlowCheetah strips additional spaces from my original config file, and thus showing lots changes. see this example image:
      here you even see spaces are stripped out from comment. Is this by design?
    • Thanks, this is likely an issue with XDT itself. There's an issue for it at Please use that link for further follow ups. 
  • New version XDT?
    5 Posts | Last post March 07, 2013
    • You mentioned adding XDT, what do I need to do with projects that were created using and old version? My concern is with other team members not having slowCheetah installed.
    • Just right click on Add Transform on some XML file. It will add the NuGet package automatically if its not installed. Then make sure to enable package restore. With package restore even if the user doesn't have SlowCheetah installed the files will be transformed. SlowCheeth (the VS extension) just provides the VS command to add transform/preview. The rest of the functionality is in the NuGet package. That's one of the great benefits of this update.
    • Sweet, that is perfect! 
      Thank you for this awesome tool!
    • Well I tested this on an existing app and it did not install any nuget package. So I installed it manually. Will that work ? 
    • Yeah that's fine, but check that you have 2.5.5 installed. 
  • Slow Cheetah transforms on Build and modifies project web.config
    4 Posts | Last post March 05, 2013
    • This is a strange one.  I had a client install the slow cheetah extension and then build the project.  The web config in the project was transformed to whichever build config was selected.  This behavior is not reproducible on my machine or my colleagues'.  This is a Visual Studio 2010 Professional w/ SP1.  One thing I did notice was he didn't have nuget package manager installed yet.  We're troubleshooting this tomorrow and I'm proposing to remove both extensions then add Nuget and last add slowcheetah (through nuget).  
      Have you seen this behavior reported before and if so, was there a set of steps to prevent it?  
    • I've never heard of this issue. Does it repro on the same box with a new project? It could be something else messing with web.config.
    • I have very similar behavior and can reproduce it with VS 2010 and SlowCheetah 2.5.5.  I create a new ConsoleApplication, add a file called testFile.config, right click and select Add Transform.  The Debug and Release Versions are added and I make slight alterations ending up with:
      <outerTag xmlns:xdt="">
      	<myDebugTag xdt:Transform="Insert"></myDebugTag>
      <outerTag xmlns:xdt="">
      	<myReleaseTag xdt:Transform="Insert"></myReleaseTag>
      If I build with Debug configuration selected, the testFile.config file is modified to be:
      Everytime I re-build, I get two additional <myDebugTag>s added.  Similar behavior with Release, it just adds two <myReleaseTag>s.  I have a colleague with version 2.5.1 of SlowCheetah and it does not exhibit this behavior.
    • Hi, I cannot reproduce this. Tried with both VS2010/VS2012 and multiple machines. Could you give specific steps that I can follow from a new project? 
  • ClickOnce for VSTO Addin for VS2010
    2 Posts | Last post March 02, 2013
    • Hi,
      We are working on VSTO Addin for Excel on VS 2010 and using this tool for transformation. When we build it is transforming, but not when we publish. And this will then be integrated for TFS builds as well.
      It seems to work for WPF and Windows publish.
      Are we missing anything here? Any pointers would be helpful.
    • I've never tried this scenario before, so am not surprised that it doesn't work. If you'd like this feature please create a new entry at Once it gets enough votes I will consider implementing the feature.
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