You can't upgrade to 8.1 Enterprise using your 8 Enterprise MAK/KMS Key. You need a genuine 8.1 Enterprise MAK/KMS Key in order to upgrade. Check with your company they should have 8.1 MAK and KMS Key. Cheers
Thanks. I'll keep that in mind (taking into consideration that I won't be near IT in at least 2 weeks, and I guess that Windows will complain about the activation before 2 weeks).
I have question regarding 8.1 Enterprise. Right now my user account is tag to a domain login. Will I lose my account if I do an in-place upgrade due to 8.1 'forceful' nature of linking it to a Microsoft Account? I lost my local account on another Window 8 installation after doing an in-place upgrade to 8.1. ~Update~ Never mind, I got my answer. One can upgrade to Win8.1 without losing your domain account (Win8.1 will not ask you to create/enter a Microsoft account).