P: Where possible, provide information about malfunction, avoid "unknown error ocurred".

All too often Lightroom shows a message like this one:
 

That is of course not helping. After so many years on the market the developers should please finally include information about what went wrong, and where. Such errors are shown frequently when I attempt to move a series of images to another directory. It is also common to see the very same operation succeeding short after, without any action undertaken.