Using CTRL+C and CTRL+V to copy the contents of a cell to another cell does calc to hang indefinitely. Only killing the process and restart is possible. As far as I can see the first Copy/Paste succeeds but leaves a selection around the cell. When deselecting the cell by doublle clicking on another cell, the selection goes away and the next Copy/Paste will succeed. If you forget to remove the selection of the previous copied cell, then the selection of a cell and Copy/Paste will have the effect that the cursor keeps turning and the application renders unresponsive.
What's your version of LO? For the test, could you rename your LibreOffice directory profile (see https://wiki.documentfoundation.org/UserProfile) and give it a new try? Thank you
I did rename the directory profile and up till now the problem seems to be solved.