Using 128GB Macbook Air with Lightroom and Creative Cloud. I back up all my photos to and external HDD to save the limited space of the 128GB internal drive. But I found out today that Lightroom or Creative Cloud is also backing up photos to the internal drive and has used up 30GB so far. Why is this happening and more importantly how do I stop it happening?
By default LR creates a catalog backup once a week. You can safely delete older backups, 3-4-5 and more weeks old, but I'd keep at least the last 2 weeks of backups.
Also there is a bug in the video cache system of LR that doesn't obey the limit set in the LR preferences. So you can go in and Purge the video cache to regain some space.
What you might be seeing is the Previews folder. You should set that limit to something like 10GBs.
Also in the import dialog make sure "Make Second Copy" isn't checked then next time you do an import of images.