Users who perform backup operations must be local administrators so that they have full control over the registry folder and the installation folder.
User credentials are not set during the agent installation. By default, the local system account is used. To access the SQL Server databases to perform backup and restore operations, SQL sysadmin rights are required.
SQL Server Is
Member of a WorkGroup
Able to back up any file and folder on the local computer to which the local group applies.
Member of a Domain
Able to back up any file and folder on the following entities:
For more information about the SQL sysadmin privileges, go to the Microsoft Support website and search for Microsoft KB article 2926557, SQL Server VDI backup and restore operations require Sysadmin privileges.
User credentials are not set during the installation process. You must select the Impersonate User option at the agent or instance level and assign a SQL Server authenticated user that has sysadmin credentials.
Note: Do not use a domain authenticated user.