WARNING: Unable to compact database
 

WARNING Unable to compact the database

That's my error, does anyone know what exactly this means or how to solve it? Thank you

I've also been having trouble save my .def files, I am not able to resave anything under the same name that I've opened it in. And when I save it under a different name the above warning in displayed, but the .def file is written. However I'm not sure if this is affected the solver capability.