How to set up OneDrive.exe as a Windows Service, allowing synchronization without a user is logged in.

Onedrive as a Windows Service.txt

OneDrive.exe as a Windows Service
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Flemming Steffensen, 2017, 2021

For our automatic build setup, we needed to fetch some files off a Sharepoint Library.
Sharepoint allows (if configured so) Lists and Libraries to be synchronized to a local folder by using the OneDrive application.
However, the OneDrive application is started when a user logs in, and in an automated build setup, this never happens.
The solusion were to disable the normal auto-start feature of OneDrive, and then install it as a service, and making sure the
service start as the computer starts.

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Edit February 2021: 
While this has been working flawlessly for me, others have had problems when Onedrive.exe were updated. In the comments below, @useyourblinker has made some observations and workarounds to deal with these issues. I highly recommend following his advice!
Additionally, @adrian-alephit pointed out a copy-waste issue with the Onedrive.exe Startup Directory in the text below. This has been fixed.
Huge thanks to both @useyourblinker and @adrian-alephit for their contribution!
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To aid this setup, the excellent NSSM tool (https://nssm.cc/) will be used.

1. Log in to the computer using the user you wish to have OneDrive running as. Ensure this user has local admin rights.
2. Install the latest Onedrive from Microsofts download page: https://www.microsoft.com/en-us/microsoft-365/onedrive/download
3. Configure OneDrive so that syncing is working. 
   If there are security issues, you may have to add trusted sites using IE: IE-Settings→Internet Options→ Security, select Trusted Sites and click on Sites
4. Go to OneDrive settings and ensure to remove the option for OneDrive to start as the user logs in.
   Note, in the future, if you need access to the GUI, you will have to ensure the service we create is stopped, before running the OneDrive.exe as normal.
5. Open a command prompt, and change directory to the place you have installed NSSM.
6. Install the Onedrive Service by issuing the following in the command prompt: nssm.exe install "Onedrive Sync NSSM-Service"
7. In the GUI that follows, configure the tabs as follows:
    Application TAB
    Path:	            C:\Users\<USER_NAME>\AppData\Local\Microsoft\OneDrive\OneDrive.exe
    Startup Directory:	C:\Users\<USER_NAME>\AppData\Local\Microsoft\OneDrive

    Details Tab
    Display Name:	OneDrive Sync
    Description:	Onedrive Sync Service installed using NSSM.
    Startup Type:	Automatic

    Log On
    This Account:	<USER_NAME>
    Password:       Correct password of <USER_NAME>
    Confirm:	    Correct password of <USER_NAME>

    Dependencies: Leave as default

    Process
    Priority:	    Normal
    Affinity:	    Select "All processor"
    Console window:	Select

    Shutdown:       Leave as default

    Exit actions:   Leave as default

    I/O
    Input (stdin):
    Output (stdout):	C:\OnedriveService.log
    Output (stderr):	C:\OnedriveService.log

    File rotation
    Replace existing...	Not selected
    Rotate files	Selected
    Rotate while running	Selected
    Restrict rotation to older	0 seconds
    Restrict rotation to bigger	100000 bytes

    Environment: Leave as default

    End by selecting: Install
8. In Windows Services, located the new OneDrive service, and change the startup settings to run as <USER_NAME> and provide the password.
9. In Windows Services, start the new OneDrive service.
10. Verify that the synchronozation is still working.
11. Log out of the account or even better, restart the computer.
12. Use your automatic build setup to verify that the synchronization is still working.

And thats all, Folks.

Thank you for the detailed troubleshooting steps, @JoelLeach - they are very valuable!

Unfortunately I'm personally unable to support this further, but I'm happy that this is still useful for a lot of people - and even more happy that people like you and others are able to support it further. Thank you!!