I am using Kile under Miktex 2.9 in Windows 10. Since I switched from my long-lasting version of Miktex to the latest version, Kile seems to frequently occasionally report ``finished with exit code 1" under the category Bibtex. It does not cause a total crushing; Kile usually proceeded to give the output with an additional input such as clicking once the space key. The little problem is just annoying.
I did an initial search with no essential improvements so far. I believe it is not my bibliography; the same bibliography, the built-in one, worked without an issue for Texstudio, Overleaf, and even Kile with the older Miktex.