I'm aware of Adobe's move to encourage Lr CC subscription. I purchased Lr 6.0 via DVD install and have upgraded to 6.10 and am satisfied with my perpetual license. However, on checking for an update Adobe removed my perpetual license and installed the subscription product.
How can I roll back to Lr 6 perpetual?
A number of people have encountered this problem. You'll need to uninstall LR 7 (Classic) and download and reinstall LR 6. See here for details, especially if you did any work in LR 7 before noticing the problem: