Isn't it easier to backup the library in MC 10, then Restore that backup in MC 11 ?
For me, if I do as you say, (which would be the logical thing), when I go back to MC10 and try to play or restore from that same MC10 backup file that was used to restore MC11, MC10 tells me the file is corrupt and can't read it and crashes.
Evidently MC11 is doing something to the MC10 zip file when I restore from it.
I end up having to delete that backup file from MC10, reinstalling MC10 before it will behave properly again. And then of course I have rebuild whatever data was lost by going back to an older backup, (fortunately, I backup almost every day).
I have to keep MC10 running because that's what my carputer uses - it doesn't have the oomph to run MC11
Both MCs are default express installations and everything is where it should be.
If anybody's got any ideas, I'd sure welcome them, because basically, I end up using MC10 to do all my ripping and tagging, (so the backups are compatable with the carputer) and have to copy those backups over to MC11 to update everytime, instead of restoring directly from the MC10 zip file.