The "offer" probably includes the ability to save the cloud data to the local system once you have a local version installed. The 2010 key will only work to install Office 2010. (Probably only the Office University 2010 that you had, and not some other, Standard or Professional, version.) To install Office 2016 you will need to purchase a 2016 key. If you are still a student, you may be able to get a decent discount on that, but not likely to be free, although not impossible either. Anyway, to use the 2010 key, find the 2010 disc somewhere in your old collection and reinstall it. Then you can use the "offer" to migrate the cloud data to your computer. Once you have a 2016 key, if you choose to get one, you can upgrade your Office 2010 to Office 2016.
Update
I haven't dealt with MS Office since 2010 versions, and avoid subscription-based services for my data. Consequently, most of the above about Office 2016 is way off base. However, misunderstandings of the "free" offer aside, the solution for you is the same.
Since you still have the 25-character product key from Office 2010, you can reinstall that. BTW some sources suggest that doing a "repair" option rather than an install will work, and experimentation with that is up to you.
First you need the installation media for Office 2010. If you have the old disc gathering dust somewhere, find it. If you don't have, never had, the disc, then MS will let you download a copy. Go to their download page, enter the product key you own and follow their instructions.
Now that you have installation media, either insert the disc, or go to the downloaded files, and run the installer. (The disc will probably AutoStart, but if not, find the disc in My Computer
and double click it.)
Depending on what the installer detects on your computer, you will have one or more of the following options: Install Office 2010
, Re-install Office 2010
, or Repair Office
. Choose the one that's available, that best fits your plans. FWIW I'd go for a complete new, total, installation, to be sure that all programs are installed, and nothing is 'linked' to the expired version you upgraded to.
Finally, save you install media somewhere in case you need it again; virus issues, buy a new computer, etc. Enjoy the perpetually licensed version, subscription free.
Best Answer
It was nothing to do with any administrator action or settings - it was because I was on a metered internet connection. When I used the yellow "connect anyway" button in the notice at the top of the main application screen, this confusing message stopped appearing.
Unfortunately, when MS added the check for a metered network, they didn't update the UI messages accordingly. So, check your network connection and if it's metered, click the yellow "Connect anyway" button, and try again, before doing any of the other steps around editting the registry.
Many online resources for this issue in Office 2013 (example) suggest editing the registry entry
Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\Internet\UseOnlineContent
, which has the following values:It appears that the Office 2016 "Metered connection" feature works by imitating a setting of 0 on this registry entry. Before Office 2016, this would have been a registry setting set by an administrator, and it seems like they didn't update the UI message to check it's not appearing for administrator-unrelated reasons.