I have a friend of mine who has a 2015 15in MacBook Pro. She still has the original Mac OS Yosemite installed & the Apple ID she used in the past cannot be recovered via yahoo email. You need to log in to the app store to download/install the new OS. So since we were unable to recover the account I just made a new (temporary) one, entered payment details and shipping, then tried to do the Mojave update... BUT when clicking "install" in the app store it would give an error message like "Unable to locate apple id" or something similar (I can't remember the exact message). So I would keep re-signing into the Apple ID and it would keep giving me an error message. She would like to update her creative cloud apps (requires Mojave) as well as just have an updated Mac OS in general. Does she need to call apple and try to recover her original apple ID that can't be recovered via email, and/or do I need to back up and re-install from scratch somehow? Thank you!!