OneDrive crippled in Build 9879

I root my User folders in the OneDrive folder which has worked fine for several years. After a day of running 9879 I restart to a warning the OneDrive cannot find the Desktop. I try to open OneDrive App and get this error: "Your System Administrator has blocked the User of OneDrive."

Googling that error I find that others are having the same problem in this build. Onedrive does not exist in new build 9879 - Microsoft Community

I cannot find OneDrive in gpedit.msc to see if this is an issue of Admin actually enabling to block its use. It is not here where the issue was solved in 8.1: SkyDrive syncing not working in windows 8.1 - Microsoft Community

Furthermore all traces of my explorer have disappeared from Start menu and Task Bar and performance is degrading to where I am now moving to boot disk to attempt repairs.

MS changed how OneDrive Works.
Testers protest abrupt changes in Windows 10's OneDrive sync | ZDNet

Testers protest abrupt changes in Windows 10's OneDrive

Not sure how those changes affected me exactly since I had all of my OneDrive files available offline. Something else must have changed that didn't like Skydrive being rooted in Storage E: or User folders being rooted in Skydrive?

It got progressively more unstable and went completely kablooey flashing endlessly at Startup between the Desktop icons and a warning box that Desktop file could not be located (it was in Skydrive on Storage partition). Too unstable to work with, wouldn't System Restore, Startup Repair, Reinstall Preview, Refresh or Reset from Disk, so I Clean Reinstalled 9860 wiping the disk including my storage partition which is in the cloud anyway.

In this install I again move my User folders to the Skydrive folder but keep it in C:\Users|Greg. I doubt whether that will sustain a stable 9879 update unless something else caused the problem. I'd probably better keep 9860 for now and enjoy having the NumLock light back on my keyboard and User folders rooted in Skydrive where they've been available Offline and synching my other devices for years.

Kind of a dark cloud over the day I deleted Win7 partition.

I assume you performed a clean install of b9879?

I swear that computers seem to "know" the best time to go wrong.
Maybe W10 was waiting for you to purge W7.

I ran this particular version update from within Settings>Recovery>Preview Builds to test it. Do you think it would have turned out differently with a Clean Install which I normally do?

I move my active User folders Documents, Pictures, Music, Downloads, Desktop, Pictures and Favorites into OneDrive folder on all of my Devices. This keeps them synched in real time.

Is there another preferred way in Windows 8 to sync via OneDrive in real time without having to move each desired file into it's folder?

A clean install seems to fix a lot of Windows problems in older versions (I know you are aware of this) and W10 TP seems no different.

There have been many comments posted on TenForums along the lines of, "a clean install fixed my problem."

If MS wants to force everyone to perform in-place upgrades (every few weeks) they are going to have to put a lot more effort into making it work properly.
If they don't they are going to have to put up with lots of complaining.

Additional
I forgot to mention that I don't use OneDrive (apparently I have one because of my TAFE email account).
I have no idea if a clean install will fix your OneDrive issue though.

I have Dropbox installed in W7, but it is disabled 99.99% of the time.

The metro app for OneDrive has been completely removed. When I did the update, I still have OneDrive but it is a very crippled version as you said. Even the Windows 7 version of the program is more useable. Similar to you Greg, I have my OneDrive folder on a separate partition, and my Documents, Music, etc. folders all point to the OneDrive folder. I did not have the same level of trouble you had however. I kind of want to go back to 9860 as well (not just because of this but because of other issues present in 9879), but too lazy to actually do it. Best of luck.

Fix here may work for others. Here's a Fix for Some OneDrive Problems in Windows Technical Preview Build 9879 | Windows 10 content from Paul Thurrott's SuperSite for Windows

I may give it a go after Clean Reinstall of 9879 to secondary partition.