Visual Studio:error MSB8020

The situation is as follows:

Error msb8020:the builds tools for v120 (Platform toolset = ' v120 ') cannot is found. To build using the v120 build tools, either click on the Project menu or right-click the solution, and then select "Update VC + + Projects ... "

Both VS2012 and VS2013 are installed on the new machine, and after you generate the Cocos2d-x project from a Python script, double-click to open the SLn file.

The default is open with VS2013, and previously compiled items on VS2012 are equivalent to re-set the toolset of the project to be used for each project in the v120

VS2013 in my hand cocos2d-x version is not supported temporarily, turn off re-use VS2012 open the project, F5 get the article beginning to show errors.  The workaround is to check whether the toolset for each project is the VS2012 desired v110. I began to toss the next, because looked at the project I set as the startup item toolset is v110, it is a bit confusing. Later running other (all normal projects) also went wrong, only to think that the libxxxx of the project was v120. is to remember, in case the next hand cheap.

Visual Studio:error MSB8020