When AutoCAD Mechanical toolset opens a drawing with external reference (xref) components, and is unable to read a source file (as in the case of the source file being renamed or deleted), the drawing opens with the source file unloaded. When the source file is unloaded, the xref components and folders from that file become unresolved, but the geometry continues to be displayed. In the mechanical browser and the structure catalog, unresolved components and folders are indicated by appending a red question mark to the corresponding icon (
).
Even though xref component geometry is displayed, the following commands cannot be used on it:
- AMSINSERT
- AMSNEW
- AMSPURGE
- AMSREPLACEDEF
- AMSACTIVATE
- AMSHIDE
- AMSHIDEEDIT
- AMSLOCALIZE
- AMSCOPYDEF
- AMSEDIT
You can continue to work on the current drawing while xref files are unloaded. However, we do not recommend it if the drawing has been ballooned. When the xref file is reloaded, AutoCAD Mechanical toolset reconstructs the Bill of Materials (BOM) and balloons may be lost.
Unloaded xref files are indicated in the Current tab of the structure catalog by the 
icon in the status column.