Autodesk AUTOCAD 2006 Command Reference Manual page 1344

Unloaded: Marked to be unloaded from the drawing once the Xref
Manager is closed.
Not Found: No longer exists in the valid search paths.
Unresolved: Cannot be read by this program.
Orphaned: Attached to another xref that is unresolved, or not found.
Type
Indicates whether the xref is an attachment or an overlay.
Tree View
Displays a hierarchical representation of the xrefs, displaying the relationships
between xref definitions. Tree view shows the level of nesting relationship of
the attached xrefs, whether they are attached or overlaid, and whether they
are loaded, unloaded, marked for reload or unload, or not found, or unresolved.
Attach
Displays the External Reference dialog box if an external reference is selected
or displays the Select Reference File dialog box if no external reference is
selected. See XATTACH.
Detach
Detaches one or more xrefs from your drawing, erasing all instances of a
specified xref and marking the xref definition for deletion from the definition
table. Only the xrefs attached or overlaid directly to the current drawing can
be detached; nested xrefs cannot be detached. An xref referenced by another
xref or block cannot be detached.
Reload
Marks one or more xrefs for reloading. This option rereads and displays the
most recently saved version of the drawing.
Unload
Unloads one or more xrefs. Unloaded xrefs can be easily reloaded. Unlike
detaching, unloading does not remove the xref permanently. It merely
suppresses the display and regeneration of the xref definition to improve
performance.
1320 | Chapter 25