When you submit a Xamarin.UITest test run to App Center Test the appcenter command uses test-cloud.exe from the Xamarin.UITest NuGet package. If the appcenter command is unable to find that executable or it finds one that is a different version than the Xamarin.UITest that was used to build the tests it will not upload the test run and you will get an error.

The appcenter command uses a simple heuristic to locate test-cloud.exe and it usually works. But, some project settings or NuGet settings can result in appcenter not finding it and reporting the Cannot find test-cloud.exe error or locating the wrong one and advising that UITest.dll and the tools are incompatible .

If the issue is that you have not rebuilt the Xamarin.UITest project after changing the Xamarin.UITest NuGet package version then clean and rebuild and try the appcenter test run uitest ...  command again. This is always a good first try.

If that does not solve the problem, the solution is to add the --uitest-tools-dir option to your appcenter  command pointing to the tools directory that has the right test-cloud.exe.

To find where your Xamarin.UITest package is located check the properties>path setting in your Visual Studio Project Explorer for Xamarin.UITest in your Xamarin.UITest project. 

References > From Packages > Xamarin.UITest (ctrl+click or right click) > properties > path

Solution Explorer > References > Xamarin.UITest (right click) > properties > path

This path will point to the Xamarin.UITest.dll and look something like (on Mac): /Users/user/.../PROJECT/packages/Xamarin.UITest.2.2.5/lib/net45/Xamarin.UITest.dll
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The corresponding tools folder for --uitest-tools-dir would be:

 /Users/user/.../PROJECT/packages/Xamarin.UITest.2.2.5/tools/ 

Make sure this folder exists and has test-cloud.exe.

Add this to your appcenter test run uitest  command (no line break)

You could  instead use a relative path based on where you are running the appcenter command.

If the packages are installed on the build machine but you don't know where and can't use Visual Studio to check the location, you can use a brute force method to find the test-cloud.exe files on your machine (you may need to vary the starting folders or drives to search):

dir d:\test-cloud.exe/s  (Windows)
​find / -name test-cloud.exe (Mac)

If the NuGet packages are not installed until the project builds, you could execute one the brute force method during the build to locate Xamarin.UITest package.

If all else fails, you can manually download the Xamarin.UITest package from NuGet, unzip it and add test-cloud.exe to your project at a known location.

If you are specifying --uitest-tools-dir keep in mind that you will need to update it as you update the version of Xamarin.UITest that your project is using.
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