Check here
C:\Users\YourUserName\AppData\Local\Microsoft\OneDrive\Update\OneDriveSetup.exe
may require a reboot.
i am having the same problem--i've had it before but eventually resolved. out of the blue, i will look in notification area and icon will be GONE. usually, in file explorer, the folder and files are still there, but without the green checkmarks. well, today, EVERYTHING is gone, and clicking on the setup file i have saved brings up the message that i have a newer version downloaded and need to uninstall this one first--which is not possible. going into the above-mentioned file and clicking on that does nothing at all as well, same with clicking on the onedrive desktop app. trying the new setup file i downloaded brings up 'preparing onedrive for first use', i hear the HD speed up-band then NOTHING HAPPENS. i cannot recall if it was something i did last time that repaired the problem, or if setup eventually did work, but i with the number of times this has happened already, i am kind of surprised it worked for as long as it did. last time this happened, microsoft told me to do the usual--reinstall the OS. i KNOW this is not necessary. can ANYONE offer any help here?? thanks.