Did a “Verify and repair”. Get the answer two missing files. Not too worried just want to get rid of the error message.
Tools > Rebuild Database. Before you do that, check Window > Log, which should still display the missing files by name.
I am an idiot. Yes there it is! Thanks. Worlds best interactive manual.
Two DTPO bought by friends so at least I am spreading the word.
Thanks Bill. All solved.