: AutoCAD will automatically detect and load the updated versions of all linked XREFs.
Technically, a "hosts" file is a Windows system file used to map domain names to IP addresses. In specific troubleshooting contexts, it is modified to block AutoCAD from reaching licensing servers to resolve validation errors. 2. Scenario A: Updating Reference Blocks in a Host Drawing
In technical AutoCAD terms, a is the main drawing that contains references (XREFs) or blocks linked to external sources. When these external sources are changed, the host file must be updated to reflect the latest data.
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.