1. Check the SDI, set to 0
2. Make sure the dxf associated with the version you want, for example: ZWCAD 2018
3. Try to download FILETYPESMAN tool to help to troubleshoot. You can compare with the OK computer. Make sure the following point:
- The type name is the right setting (following takes 2020 as an example)
- If not correct, then modify it as below figure shown, click browse to locate the ZWCAD.exe.
- Final result will be like this.
If there is no OPEN action, then right click on the empty place and choose New Action to add it.