Err, what? If that's true, there is absolutely no reason why it would happen, and also no reason why it didn't happen before. The code for this is part of the MFC framework, so not done by us. The only reason why it wouldn't save properly would be that the file is write-protected (e.g. by a virus scanner) at the time you want to save it, but that's also something that shouldn't be exclusive to this version of OpenMPT - and it should actually display an error if saving fails.