Since version 1.0.1 of BwPostman you have the possibility to save and restore the tables of BwPostman. Additionally these tables can be checked. If errors occur, then they will be repaired automatically. That works very reliable, but a hundred-percentage-guarantee I cannot give.
With this you have the possibility to de-install a totally shot to pieces installation of BwPostman and install BwPostman anew without loosing mailing lists, newsletters, campaigns or subscribers.
Save your data! This can be done with save tables from BwPostman. The reflection: “If I do some repair and something goes down in drain, then the fat's in the fire.” prompted me to code a backup routine. But the best and latest backup will be worth nothing, if I can't restore it in worse case. Furthermore it gave a restore tables, too.
Maintenance is called from main menu of BwPostman or from sub-menu. Beside basic settings, with that BwPostman can be configured and the link to the forum there are three buttons: Check and repair tables, Save tables and Restore tables.