Logic Pro X: Some control surfaces no longer work in Logic Pro X
This may happen if you were running Logic Pro 9 or Logic Express 9 in 32-bit mode. Logic Pro X is 64-bit only. This means that any third-party control surface plug-ins also need to be 64-bit. Check with the manufacturer of your control surface to see if there is a 64-bit control surface plug-in for it and for instructions on how to install it.
If your control surface worked in 64-bit mode then it should continue to work with Logic Pro X.