Access denied to save settings of options

[hopefull]

My freecommander 810a 32 bit on Win10 is much customized.
But now for some to me obscure reason I cannot modify any options anymore.
A window keeps popping up (spelled out in french in accordance to the set UI) saying something to that effect : Access denied to save settings of options.
And indeed I cannot change and save any new settings anymore
How could I fix that (without loosing all my preferences) ?
Many Thanks !

[Dreamer]

My settings or/and keyboard shortcuts are not preserved after program restart, how to solve it?