When you try and open a from a synced onedrive folder, that file hasn't download you may get the following message 

"Error 0x80070194 The cloud file provider exited unexpectedly "

Or If Onedrive icon in the taskbar keeps disappearing, follow the trouble shooting steps below:

- Confirm that the Onedrive icon is in the taskbar 

- If you click on the icon does it disappear or does it give a menu?

If it disappears follow the steps below

Press the windows key and R 

Enter the following : %localappdata%\Microsoft\OneDrive\onedrive.exe /reset

On the start menu type onedrive and open it up, click on the drive drive icon to confirm it no longer disappears.

Confirm that the original has been resolved.