The Error:
“To open this notebook, your computer must be running a supported version of Microsoft OneNote and a browser that supports opening files directly from SkyDrive.”

The Situation:
I have multiple OneNote notebooks in my SkyDrive syncing with my computer.  Including OneNote notebooks from my Windows Live Groups’ SkyDrives.  All of a sudden, when trying to open a new OneNote notebook by clicking on the link to “Open in OneNote” from SkyDrive, it tells me that I either don’t have the correct version of Office or a compatible internet browser to do this.  But I’ve been doing it for well over a year.

Obviously, something—an update or recent download—messed something up, but I was never able to determine what it was.

Searching online for a couple of hours did little to help this issue.  I finally found one guy that briefly mentioned in some forum somewhere that he did a “Repair” on Office to fix this issue.  I decided to give that a try, and IT WORKED!  Here are the steps I went through.  Hopefully this will help save someone else some time.

The Fix:

1. I checked to see what version of the “SharePoint OpenDocuments Class” Add-On that I had in IE.  Find this by going to Tools > Manage add-ons in IE.  Somehow mine had reverted to 12.x.x.x instead of 14.x.x.x for Office 2010.  So, I disabled it.  I don’t know if that is required, but that’s the way I did it anyway.
   
2. Then I went to Control Panel > Programs and Features.  I clicked on Microsoft Office, clicked the Change button at the top, and chose to do a “Repair” in the dialog that popped-up.  Then I waited about 15 or 20 minutes for that to complete.
   
3. Then I rebooted my computer.
4. Then I opened up IE9, went to Tools > Manage add-ons.  I saw that the v.14 “SharePoint OpenDocuments Class” Add-On was now there.  I then Enabled it.
   
5. I went to my SkyDrive, clicked to open my OneNote notebook in OneNote, and it worked!

Hope that helps!  Thanks for reading.