Last week Windows 10 build 9901 x64 leaked online, I snagged a copy of the .iso & installed on a VM using a non-MS account name & PW.
After the install I looked around & tested it a bit for what is new.
Today I found that one can get Cortana working after changing their account to a MS account & agreeing to several requests from her.
NTS, I have not had any hick-ups w/ this build, in a VMware install one has to change their "Firmware" choice from BIOS to EFI.
Waiting for the Consumer Preview build (if that's what they will call it) in January.
Cortana in VMware workstation 11