I downloaded fromhttps://github.com/ONLYOFFICE/CommunityServer
I opened up the Build.proj and altered the path string, that got me past the first error message, but then failed everywhere else.
In Build.proj file
Tryed to change to:
Did not like it.
And then tried change the following by placing C:\cmaster (A little more success, but then failed as you would expect in other areas.
<NuGetCommand Condition=" '$(OS)' == 'Windows_NT'">c:\cmaster.nuget\NuGet.exe</NuGetCommand>
<NuGetCommand Condition=" '$(OS)' != 'Windows_NT' ">mono c:\cmaster.nuget\NuGet.exe</NuGetCommand>
thanks for your help