OK thanks for that. I tried as you described, and after clicking Apply Changes and Restart, it quickly shut down and opened up again, and I could open a doc. However, when I closed LibreOffice down and clicked on the desktop icon of LO or an odt doc the same old problem reoccurred. It simple won’t open.
I really don’t want to have to go through the above process every time I need to open LibreOffice.