If you've previously used one of the word processor plugins to insert citations into a document and later find that 1) the plugin says “You must insert a citation before performing this operation.”, 2) the bibliography doesn't contain all citations in the document, or 3) references in a numeric citation style start from 1 instead of from an appropriate higher number, the existing citations in the document may no longer be active fields.

This generally happens if you saved the document in an incorrect file format or saved the file with another program without following proper steps to move active citations between word processors.

When using Word, you need to save files as .docx. If you save as .odt, active citations will be lost.

If you want to open a Word or LibreOffice document in Google Docs, or vice versa, you must follow an extra step to transfer the document.

You can confirm that fields in a document are no longer active by clicking them and looking for a gray highlight. In Word, you can also try toggling field codes.

If you find that your citations have become flattened, your only options are to restore the document from a backup, re-insert the citations using the plugin, or manually edit the document's citations and bibliography going forward. If reinserting citations, it may help to adjust Word field settings to always show fields in gray rather than only doing so when they are selected.