This is a known error in AutoCAD 2021 (and sometimes 2020/2022) usually caused by a corrupted Windows security update or a missing Visual C++ runtime component. The error "problem loading acadres.dll" indicates that AutoCAD cannot locate or access the resource file required to launch the interface.
If the software's configuration has become corrupted, resetting can often bypass the error. Go to the Windows Start menu. problem loading acadres.dll resource file autocad 2021
Q: I use a network license – does that matter?
A: No. The acadres.dll error is local to your machine. Network licensing does not cause this problem. This is a known error in AutoCAD 2021
Causes of the Loading Issue
Before moving files around, let AutoCAD try to heal itself. This is the most effective way to restore missing .dll files. Save and restart normally