Photoshop CS4 transforming an object

[ketchupkid]

Hello,

I'm using Photoshop CS4 on my friend's mac. I've been finding that after working on a project for a while, when I go to transform an object, even just simply resizing it, the layer duplicates and it is the the duplicated layer that gets transformed. Up to that point photoshop will have been working fine and I haven't changed any settings, it just seems to start happening randomly. How can I make it stop doing that, what am I doing wrong?

Thanks for your help!

[jno]

I'm not sure how Photoshop works on Macs, but have you tried Select All (ctrl a) before you get to work transforming?