Run Lightroom-CC (suggest open it from the Creative Cloud App)
Open the working catalog you were using with LR4
The catalog will be copied and the new 'copy' version will be updated to suit LR-CC. (-2 may be added to the catalog name)
Continue working with LR-CC and the updated catalog.
You Do not need to do any import to upgrade the catalog.
The updated catalog (v6-CC) will not open in LR4.
The 'old' LR4 catalog can be archived then deleted- after you have a reliable CC version working.
Do not open the LR4 catalog a second time with LR-CC as it will again create a second upgraded catalog.
LR4 can be un-installed so it never opens again.
I tried this and at first it didn't seem to work, but one way or another with some things I did, it all came through except the movies. Thanks for your assistance! Wayne