An error occurred while trying to load some required components

An error occurred while trying to load required components in Visual Studio 2012

This could be the case happening while installing Office Developer Tools in offline mode and then started creating SharePoint projects using Visual Studio 2012

An error occurred whilst trying to load some required components, Please ensure the following prerequisite components are installed.

Microsoft Web Developer Tools

Microsoft Exchange Web Services

The possible reason could be while installing the Office Developer tools and prerequisites, the office web installer sets some parameters mapped to GAC, which is not done while installed in offline mode according to following link
http://blogs.msdn.com/b/timquin/archive/2013/01/22/setting-up-visual-studio-2012-for-sharepoint-2013-development-offline.aspx

The fix this try the following steps:
- To un-install Microsoft Exchange Web Services from Control Panel
- Open the 'Command Prompt' with Administrator Previliges
- Navigate to location of file EWSManagedApi32.msi from the Command Prompts
- Run the following command. Make sure to be in single line. There is 'space' between .msi  and addlocal

  EwsManagedApi32.msi addlocal="ExchangeWebServicesApi_Feature,ExchangeWebServicesApi_Gac"

- The installation of the Exchange Web Services Api finishes. This commands does the installation and as well as maps the required dll files in GAC.
- Try closing any open instances of Visual Studio. Restart the Visual Studio
- Enjoy creating SharePoint Projects.

Hope this helps!

Thanks,

Vinay.