@kilroyscarnival

Thanks for your input. I did try the Repair function, but it did nt correct the problem. In fact, I have now managed to reinstall the Office Suite and I appear to be back on track.
The dictionary that went missing is the generic one (UK) that's installed with Word. My custom dic., like yours, contains hundreds of technical terms (mainly for glassmaking) and this seems unaffected.
Pinned docs all look fine.
Thanks again,
David