Platform: Mac / Application: AutoCAD
If AutoCAD returns with the above error message when opening an AutoCAD document (.dwg files) then first check that with other colleagues using AutoCAD to see if they have the same AutoCAD document open and if ask if they can save and close the document.
If no other users have the AutoCAD document open then it is possible that the document is locked for editing. This error is usually a result of a previous session when the AutoCAD document was opened and the AutoCAD application crashed or was Force Quit leaving the document locked due to the ungraceful closure of the AutoCAD application.
To resolve this issue select the AutoCAD document (single-click to highlight the document) and then click on the FILE menu and then select DUPLICATE. Now open the duplicated document in AutoCAD, close the duplicated document, and then deleted the duplicated document. Now open the original AutoCAD document and now it should hopefully not display the returning error "docname.dwg is currently in use or is read-only".