Starting with AutoCAD 2018, Autodesk implemented a change where the Host file retains the block definition data of an Xref even after it is unloaded.
You have two options:
Option A: The DesignCenter Approach (Manual) autocad block host file updated
Option B: The Tool Palette / $m Macro Approach (Automated)
Create a button or tool palette tool that always pulls from the host file: Starting with AutoCAD 2018, Autodesk implemented a change
| Do This ✅ | Avoid This ❌ |
|-----------|---------------|
| Store the host file on a fast, reliable server. | Save it on your local C: drive (others can’t reach it). |
| Use a naming convention with versions (e.g., Blocks_v2.dwg). | Overwrite the host file while users are actively inserting from it. |
| Run AUDIT and PURGE on the host file weekly. | Define blocks with the same name as standard AutoCAD blocks (e.g., Table). |
| Notify the team via chat/email when you update. | Assume AutoCAD will automatically "see" the changes—it won't. | Option B: The Tool Palette / $m Macro
In older releases (2019–2022), a bug existed where opening a drawing with proxy objects (objects created by vertical products like Civil 3D or AutoCAD Architecture) would erroneously trigger a "Block Host File Updated" for the *Model_Space block—a systemic error.