Red X's instead of Tool Icons

In some cases, you may see red X's in place of tool icons in your Vectorworks palettes.
 

This can occur for one of the following reasons:

The tools that are not appearing were part of a set of 3rd party plugins.

To fix this:
Reinstall the 3rd party plugin as detailed in the instructions for that specific plugin.

You brought your workspace from a much older version of Vectorworks.

To fix this:
You should reset your Vectorworks preferences and use the default workspaces provided with your current version of Vectorworks. (Instructions for doing this can be found HERE.) Then you can customize the newer version of the default workspace to suit your needs.

If you updated your operating system, or performed a migration from one computer to another that included the Vectorworks application, specifically using the Apple Migration Assistant. 

Or, Vectorworks was updated while the application was still open. 

Or, the plugin is no longer in the plugins folder.

To fix these:
You must first uninstall Vectorworks completely (instructions for doing this can be found HERE), then reinstall and update to the latest service pack for your version.