The best format for importing records from Citavi into Zotero is Citavi XML. This format will import the item bibliographic metadata, as well as quotations, tasks, attachments, etc. Zotero can import files exported from Citavi 5 and Citavi 6.
ctv6bakand lies normally in your home directory under
Documents\Citavi 6\Backup(i.e., follow this format
C:\Users\<username>\Documents\Citavi 5\Backup\<projectname>). Alternatively, you can look up the backup folder under Tools / Options / Folders and there click on “Open folder with Windows Explorer”, see https://www.citavi.com/sub/manual5/en/101_backing_up_your_projects.html.
ctv6bakfile is a zip file, which cannot be processed directly. You must first unzip it and continue with resulting unzipped file.
ctv6file you are importing. Citavi will save all attachments in the project folder (e.g.,
C:\Users\<username>\Documents\Citavi 5\Projects\<projectname>\Citavi Attachments). Copy them from there.
ctv6file in Zotero.
ctv6file. However, you can save the annotations into the PDFs itself in Citavi before you start the Zotero import.
As an alternative to the above procedure, you can export your Citavi library in the RIS format. This format will only retain item bibliographic metadata. Any additional item elements, such as citations from the “knowledge management” functionalities in Citavi, will not be included.