When making changes to database entries in CSD Editor the structures are saved as a separate CSD Editor session file. If you attempt to re-open a database as part of a pre-existing session it may cause an error message to occur stating:
To resolve the error: First close the CSD Editor session, and then locate the folder containing the CSD Editor session files (typically C:\Users\USERNAME\csd_editor) and delete the files present. Once these files are removed CSD Editor can be reopened and used as normal.
More information can be found in the CSD Editor documentation, available from the Support & Resources > Downloads section of the website.