Canon Ixus 750 Memory Card
When I put my SD in my Canon Ixus 750 comes with a message?

Every time I put on my SD Canon Ixus 750 that comes with "card error Locked memory card, "but the real lock on the SD card isn't locked. It workes fine on my camera.

I guess you're trying to use card 4 GB or larger, and that the 750 simply can not handle the new technology.

Canon Ixus 750 Memory Card