I have a Mac computer and use LRCC 5.7. I now have LRCC 5.10.1 and don't know how to move all my photos to the new upgrade.
Anyone know how?
I now have LRCC 5.10.1
I assume you mean LR CC 2015.10.1.
Is your Cloud Lightroom on the same computer as your old LR 5.7? If so, just open the old LR Catalog from LR Cloud and it will be converted to LR Cloud version and find all your photos exactly where they are.
There is no 'moving' of photos involved. Do NOT try any importing of photos that are already in your catalog.
You simply open your (5.7) catalog that you have been using and Lightroom will upgrade it (after it makes a copy).
( a Double-L-click on the .LRCAT file will open the catalog.)
Then continue using Lightroom.
Post again if you need more information.