ShellExView (by Nir Sofer) is an excellent tool to view and manage all installed shell extensions. If available, it displays the description, as well as version details, company information, location, file name and more. You can optionally disable/enable any item, which can be very useful to disable an extension, that you don t need or that has been left behind in your right click menu from a previous software install.

Effective usage of ShellExView to resolve the right-click problems
Download ShellExView and run it. It will scan the registry for all the shell extensions. Once the scan is over and the list is displayed, you need to spot the context menu handlers. Sort the results using "Type", so that the context menu handlers are displayed together.

The rule is to disable non-Microsoft context menu handlers *one-by-one* and verify if the problem is solved. If disabling one does not solve the problem, undo the disabled item and disable the next non-Microsoft handler. Do the same until the problem is solved and finally identify the culprit. Scroll right to see the Company Name column in ShellExView.

Ну и глянте в регистр
Registry Key Description
HKCR \*\shellex\contextmenuhandlers Files
HKCR\AllFileSystemObjects\shellex\ contextmenuhandlers Files and file folders
HKCR\Folder\shellex\contextmenuhandlers Folders
HKCR\Directory\shellex\contextmenuhandlers File Folders
HKCR\<ProgID>\shellex\contextmenuhandlers File class
HKCR\Directory\Background\shellex\ContextMenuHandlers Desktop

HKEY_CLASSES_ROOT \ Directory \ Background \ shellex \ ContextMenuHandlers