I’ve tried to open a DWG with header AC1009 in versions 16.12.1 (production) and 18.3.0 (testing). I don’t expect it to work with 16.12.1, but I do expect it to work with 18.3.0 considering your site’s list of supported DWG formats, which includes R11/12. I can send the file privately if you need to see it.
Error: “The Dwg version is invalid…”
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