Preserve original 'Date Added' for Imported Collections

When I export a Zotero Library in Zotero RDF format with notes and files e.g. for bac-up purposes, etc., and import them again, Zotero does not retain the original 'Date Added' but uses the date/time of import for the imported collection; in which case, the 'Date Modified', at least initially, is the same with date added. Although 'Date Accessed' still retains the original date accessed for websites and downloaded articles etc., this is not applicable for all item types: for instance, for article citations, which do not have any web links or downloaded pdf attachments etc., you do not have any 'Date Accessed', hence, no way of preserving the original date one has added such data to the library.

So I'd like to ask whether there is a possibility to retain the original 'Date Added' for the Zotero Library RDF exports/imports? Could there at least be an option to preserve the original Date Added when exporting&importing Zotero libraries? Thanks.
  • It's not an unreasonable request, but note that Zotero RDF is not meant for back-up.

    To back up your library, back up the entire Zotero data directory.
  • Thank you - no, back-up was just for example, for which there are already better ways as you pointed out. My point is rather being able to preserve the original Date Added for exported items. Imagine this: I have built up a number of Zotero databases over years, in a number of computers and operation systems (including Virtual OSs), and now I want to consolidate my Zotero library 'assets' in one place. Due to the large number of Zotero libraries and limited cloud storage I have for the moment, I do not go for the online synchronisation route but rather, I want to do this by exporting all different Zotero libraries and then importing those into one single Zotero library, consolidate items and remove duplicates.
    In such case, for instance, a note from the year 2008 is imported as if it is first created/added to the library on the date it is imported, as the Date Added is the same with the date imported. What I would like is an option to preserve the original Date Added for such imported items and the import date to be reflected in the Date Modified field. In this way it would be much easier to consolidate the library with all original dates etc. of such items preserved, and you retain the backward history of your own Zotero library.
    Thanks again.
  • You can do this by online synchronisation without needing any cloud/WebDAV storage-- simply set them all to sync to a single Zotero account.

    You can combine attached file storage by carefully copying the contents of the "storage" directories inside your Zotero data directory-- just watch out for folder name collisions (fairly unlikely) as you merge them.
  • ajlyon, thanks for the suggestion - this would be a relatively easy solution if I didn't have duplicated libraries here and there - and differentiated from each other over time in terms of contents (attached notes, relations, links, etc. to an initially same item in two libraries). I do not know and hence not sure whether sychronizing without attachments - and then merging the zotero 'storage' folders would help me consolidating my library without losing any content. If so, then this would do. In any case, I still think ability to export with the original 'date added' could be more useful in some cases than it is now - e.g. when one wants to export some portion of her/his library to another colleague for a research project, this would ad an extra time-tracking option for the researchers (which item is found when? earlier-later, etc.)
  • As I said, I'm pretty sure that what I suggest above will work to merge these libraries.

    The problem I see with importing date added is that imports come in all flavors-- how do we distinguish imports of data from colleagues from the data you just downloaded from a journal database? We could export it, I suppose, in those formats where it makes sense (probably RDF exports, not sure about others).
  • Thanks, and as I said, then this would do - for the library consolidation I described.

    My original suggestion above for exporting with original date added was also focused basically on Zotero RDF format, I still think such an option would make perfect sense. Date added is a time category which you cannot change easily (i.e. you cannot easily change the date added for an item in a Zotero library) and the original date added data is actually lost data during export/import. On the other hand, for distinguishing data from other colleagues, I think tagging & collections would help sufficiently enough; as is the case for me while using group libraries. As such, I cannot see any problems, maybe I am missing something; maybe it would be problematic for other export formats than Zotero RDF, which I scarcely use and therefore not knowledgeable of.

    Anyways, returning to my feature request, I think adding an 'option' to Zotero RDF Export to preserve the Original 'Date Added' data of the exported items would be a helpful feature in terms of not losing the original date/time data pertaining to an item and hence improve the comprehension of the time scale in extensive Zotero libraries (which item is found/ added when? etc.). Thanks again:)
  • Has this feature been added? That is: is it possible to import from another reference manager to zotero without loosing the date when each record was originally added (and I might add: last modified)?
  • No (though I think it's included in the Mendeley importer? -- not tested, though). But since these aren't included in any export format, this was only ever an option for Zotero to Zotero import/export anyway.
  • I could really use it (BBT does output it in its own internal exporter)
  • Ah and some bibtex files have date added.
  • edited March 31, 2021
    you also get the "date added" when exporting from citavi (via the citavi backup file, as described here: See also here:
  • Same question here: will there ever be an option to retain the original "Date Added" in exports and imports? I use this for importing students' databases. From Zotero to Zotero
  • Wouldn't a copy of the students databases via shared groups retain fate added / modified though? That seems easier if it works.
  • edited April 18, 2021

    Entries do not have to be imported using BBT. The only thing that matters is that the dateadded/datemodified information is in the "extra" field.
  • thank you. I will check this but it seems some change of workflow: we use a regular ex- and import to and from RDF. On laptops. I cannot connect your provided URL to this issue. And I do not know where Date Added is stored, but I never find such info in the Extra field. Extra is usually empty in most entries.
  • edited April 18, 2021
    You'd have to add it before you import them. For BibTeX imported with BBT, it is added by default if you have timestamp (or similar) fields.
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