Veeam Agent backup job targeted at OneDrive fails with Key not Found

Challenge

A Veeam Agent backup job targeted at the Microsoft OneDrive cloud storage fails with the following error:
Key not found Failed to establish connection to OneDrive Agent failed to process method {Cloud.AddConnection}. 

Cause

The issue occurs because of recent changes in the Microsoft Graph API.

Solution

To resolve the issue, apply the hotfix as follows:

1. Download the hotfix.
2. Stop the Veeam Agent for Microsoft Windows service (VeeamEndpointBackupSvc) and exit the Veeam Agent tray application.
3. Rename the following files: 
   • C:\program files\Veeam\Endpoint Backup\Veeam.Backup.Core.dll into Veeam.Backup.Core_old.dll
   • C:\program files\Veeam\Endpoint Backup\x86\VeeamAgent.exe into VeeamAgent_old.exe
   • C:\program files\Veeam\Endpoint Backup\x64\VeeamAgent.exe into VeeamAgent_old.exe
4. Go to the folder where the downloaded hotfix is located (step 1).
5. Copy the files from the hotfix archive to the C:\program files\Veeam\Endpoint Backup. 
   • If you are working with the x64 OS, copy the Veeam.Backup.Core.dll file and all files from the ForX64OS folder.
   • If you are working with the x86 OS, copy the Veeam.Backup.Core.dll file and all files from the ForX86OS folder.
6. Start the Veeam Agent for Microsoft Windows service (VeeamEndpointBackupSvc) and the Veeam Agent tray application.

More Information

[[DOWNLOAD|DOWNLOAD HOTFIX|https://veeam.com/download_add_packs/backup-agent-windows/kb3139]]

MD5: 932fd6a11e3e6af71b3b0866587b1549
SHA-1: 4c59bd38f550d0a02b639f0d41a951ed5c802ead