but what I cann't understand at the moment is, that if You don't have the part anymore as well as the material db, what prevents You from defining thematerial new?
Or if You don't need it anymore, there is even no need for it, isn't it?
Since a reinstall of Solid Edge hasn't change anything, I must assume that the material was defined by Yourself.
What I can recommend as principal is, to hold all Your personal data, options, settings - and material belongs to that category, within a special folder rather then to let it in the default directory of the program.
Latest when installing a new version can let You forget to copy thos material, hole, etc. files which then will be lost for the new version.
And having this files at a server will normally provide a backup of them for worst case situations.
But to be honest, man always knows things better after the happend!