Each time I try to install the DotNetCore.1.0.0-VS2015Tools.Preview2.exe package I get an error saying the following:
Setup Failed On
Know issues, https://msdn.microsoft.com/en-us/vs-knownissues/vs2015-update3-rc, details a similar issue with preview1.
May be worth keeping an eye on for updates about preview2.
I have the same issue but haven't solved it yet. My version numbers are different to those listed for the fix for preview 1, this answer is just pointing you to the official issue page.
[Update] the official word on this is at https://github.com/aspnet/Tooling is
"Due to a known issue in the setup detection logic, even though you have Visual Studio 2015 Update 3 RC installed, you might see the following message when you run the installer. This will be fixed in the next build. For now, to work around this and bypass the check, you can run the EXE from a command prompt and then pass SKIP_VSU_CHECK=1 at the end. "
[Update 2] - for in-depth info on upgrading to rc2 from rc1, David Pine's blog on the steps required is very good.
ievangelist dot github dot io /blog/migrating-to-rc2/