It does seem as though it is a corrupt catalogue. When I created a new one it did that OK, but then tried to close the old one and again froze. I Forced that to close and the new one opened and would close correctly.
I can set the new one as default by using Cmd+icon to open and then selecting it and setting it as default, but how do I then transfer all the data without transferring the error?
Trying to import from other catalogue I get:
"Can not import from this catalog at this time. The catalog is either in use by another copy of Lightroom or was closed improperly. If it was closed improperly, please consider doing an integrity check when opening".
Tested integrity on opening - still opened, but still failed as before.
Thanks for this, by the way
is there a way to repair it?