I am having the same problem everyone else is when installing Visual Studio 2015 with Update 1. It is failing on the Team Explorer install and as far as I can tell it is being caused by the same error outlined in this question (Multiple Errors Installing Visual Studio 2015 Community Edition). I have tried the steps explained in the answers to that question, including the answer that is in Russian. However, the installation is still failing at the same point. I am at my wits end now and out of ideas to try.
Can anyone help?
Well I ended up opening a technical support case with microsoft to resolve my issue. They found the issue below in my log files:
The actual problem
As you can see, this is a known issue with Microsoft. I asked for alternate suggestions to get this installed and the support rep asked me to do a clean install with the non-update 1 version of VS Enterprise 2015. I follow the instructions below to perform a clean install and it worked.
The actual solution
And... tada, the installation was finally successful! I hope this helps others that have a similar issue that isn't resolved by repairing the C++ runtimes alone.
Once RTM was installed successfully I was able to run the Update 1 installer and update successfully. Since then, I have also installed Update 2 with no issues.