I hope you have better luck than me. I had the same issue, new HP laptop with 256Gb SSD. So I followed all the instructions, put the library and all files on an external drive, installed iTunes on the new laptop, went to Edit\Preferences\Advanced and set the new location for the library and checked the box to keep my library organised. That should have worked, but it didn't. iTunes didn't see any of them. Every file was awaiting download. Left with little choice but to download them all. At least they went to the external drive(Copy elsewhere and delete first or you will have two copies of every file). but it took nearly two days.