AutoCAD: The security system (Softlock license manager) is not functioning or is improperly installed

This error can happen if you have a corrupted installation of an Autodesk program or if the License model has been changed in the registry. In most cases a clean uninstall and reinstall should correct the issue. However if this issue is not resolved then delete the licensing files and reactivate the product.

License files location

On Vista \ Windows 7 \ Windows 8\ Win 10:

C:\ProgramData\FLEXnet\adskflex_00691b00_tsf.data

C:\ProgramData\FLEXnet\adskflex_00691b00_tsf.data.backup

On Windows XP:

C:\Documents and Settings\All Users\Application Data\FLEXnet\adskflex_00691b00_tsf.data

C:\Documents and Settings\All Users\Application Data\FLEXnet\adskflex_00691b00_tsf.data.backup