Source Drawing ... Not Found (Using the AutoCAD Sample Files/Tool Palettes)

Issue

You're trying to use the AutoCAD sample files (tool palettes) and received an error similar to the following:

Source drawing "(drawing name)" for block "(block name)" not found.

For example, you might have been trying to use an AutoCAD dynamic door block to add doors to a building in your drawing, but you received a message that the source drawing for that block is not found.

Cause

The source file for the block you want to use is missing from its usual location.

Solution

You can download any AutoCAD source file from the the Autodesk sample files page.

Once you've downloaded the file(s) you need, drag and drop them into the folder C:\Program Files\AutoDesk\(your year version of CAD)\Sample\en-US\DesignCenter.