Select your user profile and ensure and Write are checked.
The error appears when AutoCAD attempts to create or modify a file ( .dwg , .bak , .ac$ , or temporary lock file) and the operating system denies write access. Make Sure You Can Write To Current Directory Autocad 2013
Elias tries clicking "OK" over and over, but the message won't budge. He realizes that Windows is protecting his —specifically the Program Files folder—preventing his activation tool from creating the temporary "write" files it needs to finish the job. How the Story Ends (The Fixes) To resolve this, Elias (and you) can follow these steps: Select your user profile and ensure and Write are checked