Is possible that editing database files or starting new game cause damage saved game?

Is possible that creating new database files, editing existing database files or starting new game will cause damage my saved game? (of course I know, that I can;t edit my database file used to start saved game). (FM2011)

I’m playing my career for long time (based on edited database) ind don’t want to lost it, but I would like to test other databases in other leagues.

I would like to be sure, that such activities don’t cause problems with my saved game for example after a few seasons, with transfers, finances, reputation etc.

As long as you specify the exact database that you want to use when starting a new game, then this will not affect your current save as it will be usuing its own edited database.

But what will happen if I will use (by mistake) default database 11.3.0 a for start new game?

This will not affect your current save which is using an edited database.