Hi there, I think I have the same problem. I've been using KeePass for a long time, adn now I've had to format my pc (windows) and I backed up the .kdbx file. Now I have installed again (in the new pc) the KeePass and I double click the .kdbx file and I get the message that the composite key is invalid!, and I write Ok the master password (I did twice). How about the solution of these issue??? thanks in advance