Updated my primary home desktop to OS X Mountain Lion this evening and of course I ran into an issue with the Microsoft SkyDrive app (which I use regularly). After completing the upgrade, I was presented with an error message basically indicating that SkyDrive could not authenticate with the KeyChain. Luckily, there is an quick workaround until either Apple or Microsoft addresses this issue.
1. Launch Keychain Access from /Applications/Utilities
2. Select the login keychain from the list on the left
3. Locate the SkyDrive Cached Credential item and select it
4. Go to File/Get Info
5. Select the Access Control tab
6. Click to select Allow all applications to access this item
7. Click Save Changes
The alternative would be to transfer files back and forth between my computer and the SkyDrive website instead of using the convenient Finder integration have been used too. This is just a temporary workaround and hopefully a more permanent fix will be delivered soon.