Database locks when phrase searching

[StephenUK]

I think I can partly answer my own question. The database became corrupted , but using Ctrl Alt Del to access Windows Task Manager, and by deleting the UR process (rather than application) shown there, the database righted itself (even though rebooting had not achieved this effect).

Searching is now as it should be. I suspect I somehow created a rogue search which locked the system and which was repeating the problem when the search box was re-opened after re-boot.