I too am experiencing the same problem. OneDrive has always worked fine until this week - the OneDrive folder, subfolders & files are there in File Explorer, and can be opened, however Onedrive wouldn't sync with online files, and I noticed that the icon had disappeared from the Taskbar. On locating OneDrive.exe in the OneDrive folder and clicking, nothing happened.
I managed to locate in C:\Users\NAME\AppData\Local\Microsoft\OneDrive\Update\OneDriveSetup.exe and on running it, it installed OneDrive, but a message said it was "preparing for first use". It only took about 1 minute to run, but lo and behold it worked, and it re-instated the Taskbar icon too. This worked for a couple of days, then it was same again, so re-run the installation file to get it working again, the second time being yesterday, 14/07/2018.
I came on here to try to find out why this is happening and a possible cure, and have has mentioned here, found in the OneDrive folder a subfolder - in fact, now 3 subfolders, the latest one being 18.111.0603.0006_1. In each of these folders there is a OneDriveSetup.exe file.
At least it gets it up & running again, but it's a nuisance if I have to do this every couple of days.
Trevor B