I little window said free upgrade which when clicked asked me for my apple ID and password. So far so good. After that the same window changed to install apps which when clicked which again asked for my ID and password. This time it wanted my credit card etc. so I gave up. Is Mavericks free or what? jaybass
It is free, but since you are downloading through the App Store you apparently need to meet that venue's requirements, one of which is that you register and provide a credit card for any
future purchases (even if you have no intention of making any).
There may be a way to use the App Store without providing a credit card number, but that's another issue.
