customized metadata not available

Hi all I am using Calibre on a Mac since years. What I noticed yesterday is that my customized columns, e.g. read book yes/no etc. are no longer available. Could be happened some weeks before and I didn't notice it directly. I did a lot of copy and paste (from the calibre LIBARY FOLDER) with Time Machine backups but no solution. Is anyone aware where exactly the additional metadata or all data are stored? I have my book library on A shared "one drive".

Thanks in advance
Marco