In Visual Studio 2017, they changed the path to vsdiffmerge.exe to
VS2017 Professional
"C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer\vsDiffMerge.exe"
VS2017 Community
"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer\vsDiffMerge.exe"
I tried to follow instructions on https://github.com/Inmeta/Knowledge/wiki/Setting-Up-DiffMerge to configure git to use Visual Studio Merge Tool as external diff tool as I used to with VS 2015 and prior.
In Visual Studio 2017, they changed the path to vsdiffmerge.exe to VS2017 Professional "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer\vsDiffMerge.exe" VS2017 Community "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer\vsDiffMerge.exe"