In that case, if you really want the items, you can try using Delphy's Multi-Extractor and installing the content in. This is a useful test for whether the items themselves are corrupt: if they won't install properly in a clean folder, they're probably just not going to work at all. If that doesn't make a difference, move the entire Sims 3 folder to the desktop, open the launcher to spawn a clean folder, and try to install these same items that have been giving you trouble. For now, just see whether this helps you install the new items. dbc file will uninstall the most recently-added custom content, but you can reinstall it later. They'll be labeled dcdbX.dbc starting with zero. dbc file with the highest number in its name. Please go into Documents > Electronic Arts > The Sims 3 > DCCache and remove the.Information, Guides and Announcements for the EA app.
