I bought new iMac, huge screen...xcant wait. anyhow, migrated all files from old macbook to new iMac. All images presets etc on ext HD... LR does not see HD says I have no images. SUSPECT THERE IS A MYSTERY BUTTON SOMEWHERE hehe. help me reconnect. want to use new computer!!!!!! waaaaaa
Did you transfer the catalog file to the new computer and then open it?
If so, please read this document:
If not, then that's what you should do. More details: How do I move Lightroom to a new computer? | The Lightroom Queen