Specified platform toolset (v110) is not installed

I have a solution initially created using VS2010. When I opened it using VS 2012, it asked me to do some conversion, which I agreed. Now I'm using VS 2010 to open the solution again, and when I tried to build it gave an error:

error MSB8008: Specified platform toolset (v110) is not installed or invalid. Please make sure that a supported PlatformToolset value is selected

How can I fix it? For example, is there a way to change the platform toolset to v100 again?

Yes indeed it is:

• Right Click project
• Select Properties
• Select Configuration Properties
• General
• Platform Toolset

When you get to Platform Toolset, click on the v110 value which will be in the right column. You will see a drop down appear which will allow you to select v90, v100, or inherit. Of course, v100 is the correct answer. Once v100 is selected, I don't believe you can back to v110 from within VS 2010. You would have to once again open in in VS 2012 to move it back to v110.