ERROR - BibTeX subsystem: /tmp/i_hu76qDT8/References.bib_3533.utf8,
line 2, syntax error: found "{o}", expected end of entry ("}" or ")")
(skipping to next "@")
INFO - ERRORS: 1

documentclass{report}
usepackage{biblatex}
addbibresource{References.bib}

begin{document}
John S"{o}ren wrote cite{TestEntry}.
printbibliography
end{document}

@InCollection{TestEntry,
   author    = "John S"{o}ren",
   booktitle = "Nonesuch",
   publisher = "Some Publisher",
   address   = "Somewhere",
   year      = "1996"
}

author    = "John S"{o}ren",

author    = {John S"{o}ren},