Move a Drupal site to a subdomain
Usually there is no problem in moving your Drupal site to a subdomain but TinyMCE likes to use absolute URLs which can break things when you move your site to a subdirectory.
You can fix this by using the Pathologic module.
If moving to a subdirectory, simply enter a single slash in the 'Additional paths to be considered local' configuration section described in the Pathologic documentation.