Error message “Installing package VeeamWANSvc_x64.msi Error: Error 1920. Service Veeam WAN Accelerator Service (VeeamWANSvc) failed to start. Verify that you have sufficient privileges to start system services.” appears when trying to add a WAN Accelerator in the Backup Infrastructure. Trying to install the service manually on the proxy also fails.
The service installer is pointing to an invalid path in the Registry on the server. This occurs most often when the role is removed from the server, then the original drive used for the WAN Accelerator cache was removed.
On the WAN Accelerator server having an issue reinstalling, open regedit and browse down to the following location:
HKLM>Software>Veeam>Veeam WAN Accelerator
Find the following Registry Strings and modify to point to a valid directory path: