Why libreoffice always reset to default setting when os updating or libreoffice updating?

I modified the font for new document and available of OpenCL then save the setting. However when the Operating System is updated or LibreOffice application is updated, all the setting in LibreOffice would reset to default.

Where these setting save?
How can I keep my custom setting eternal?

Read these guidelines and ask good questions. In particular, keep headings short.

It has never happened to me. Anyway, back up your user profile and restore it as necessary.