A ServiceDesk installation or upgrade requires a domain user account that has sysadmin rights in the SQL Server that ServiceDesk will be using. If a different account is used, such as the ServiceDesk service account, the installation will fail. You want to know if you are using the right account and if it set up correctly in the SQL Server.
Verify that the domain user account to be used is set up in the SQL Server with sysadmin rights and that this is the account that is logged in during the ServiceDesk installation. (This, or a similar account, is needed for new installs, reinstalls, or upgrade installs.) This is known as the "Installation Account". If the Installation Account is not used, and the Service Account or a different account is, then the installation will fail. Refer to the Additional Information on Servicedesk User Accounts section at the bottom of this article for more information.
How Install and run ServiceDesk with a domain account instead of a local system account
Additional Information on ServiceDesk User Accounts
ServiceDesk uses two domain user accounts:
Errors during the install that refer to permissions or database issues occur almost always because the user is not logged in as the correct domain user, the Installation Account.