Slow cheetah Add Transform does not appear

The issue is, only adding nugget would not suffice. You need to install slowcheetah from visual studio marketplace. Following are the steps:

1. Install SlowCheetah from Tools > Extensions and Updates
2. Restart VS, allowing for the VSIX installer to run
3. Create new C# App (.NET Framework). (In my case, it started to work on existing app also.)

GitHub Reference

I had the same issue. I installed the NuGet package 2.5.48 and then was able to download and install the vsix file from here and it worked:

https://github.com/sayedihashimi/slow-cheetah/releases

As a work-around you could do this by hand. Make a copy in the _Solution Explorer* of your Web.config and rename it to Web.Debug.config or whatever you like.

Unload the project and then Edit the project. Find the ItemGroup element that contains your newly created config file and add the <DependentUpon>Web.config</DependentUpon> element there, like so:

After that, it will look like this in the Solution Explorer:

Now you can edit your newly added config file with the required transformations.