Fix - Error in lc.exe when Compiling Solution upgraded to Visual Studio 2017 RTM from Visual Studio 2015

Upgraded our product solution today to the latest Visual Studio 2017 RTM and everything seemed to work fine - until I started getting the following error in the build:

"The specified task executable "lc.exe" could not be run. The filename or extension is too long"

What is this lc.exe command and why is it running? It is used by the standard .NET licensing mechanism and is maintained by Visual Studio for information about all licensed components.

In my case, the error was occurring in "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets" Line 2975 according to my error log.

Clearly this problem was related to the fact we are using Telerik Controls which require a licx file to compile (or so I thought).

I turned on full diagnostics in Visual Studio 2017 to help get to the bottom of the issue:

This showed the full path that was being passed to lc.exe is over 42000 characters long (!):
1> C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.6.1 Tools\lc.exe /target:ESSP.ApplicationPages.dll /complist:Properties\licenses.licx /outdir:obj\Debug_SP2013\ ....[SNIP]
 

Several places such as on Microsoft Connect - suggested that the "solution" (pardon the pun) is just to delete the licx file (also as per http://docs.telerik.com/devtools/aspnet-ajax/licensing/license-file) I could then recompile without any build exceptions.

This issue comes about because the lc.exe executable can only handle a parameter length of 32000 characters or less - and the full path is used for all references. Needless to say this is a restrictive limitation in the licensing mechanism!

So the possible alternatives to fix this issue:
1) Remove the licx file if possible when you don't need the full licensed functionality (in my case this was fine - as we don't need design mode for the Telerik controls).
2) Reduce the length of your references by adding a shared drive or logical redirect to a shorter path e.g. c:\references instead of c:\src\DDK\product name\releases\ etc)
3) Reduce the number of references that you have in the project that has issues with lc.exe

DDK