The user domain\vsa is not a member of the local administrators group on file server: c-mode.domain.com. The user domain\vsa should have full control to the files & shares you wish to archive.

This looks to be an issue with a check performed against the C-Mode target file server and the result is reported incorrectly.
This failed return does not cause issues with normal operations of Enterprise Vault File System Archiving.
This issue is addressed in Enterprise Vault 14.1
The Deployment Scanner results for File Server Permissions incorrectly displays the that Vault Service Account (VSA) is not a part of the Local Administrators group on the NetApp C-Mode server.
JIRA: CFT-3238 ETrack: 4020898