Resolution:
For Windows Engines:
When you are running the Engine Service as a user other than the local system user and want the Engine instance to RunAs while executing tasks from a service, do the following:

   1. Set Engine Permissions as mentioned in the Installation Guide.
   2. Set read/write access to the Engine installation directory for the RunAs user.
   3. Add the RunAs user in the appropriate policies in Windows User Administration. Do the following:
         1. From the Start menu, click Administrative Tools, and then click Local Security Policy.
         2. In the Local Security Settings dialog box, double-click Local Policies, and then double-click User Rights Assignment.
         3. In the details pane, double-click Adjust memory quotas for a process. This is the SE_INCREASE_QUOTA_NAME user right.
         4. Click Add User or Group, and, in the Enter the object names to select box, type the user or group name to which you want to assign the user right, and then click OK.
         5. Click OK again, and then, in the details pane, double-click Replace a process level token. This is the SE_ASSIGNPRIMARYTOKEN_NAME user right.
         6. Click Add User or Group, and, in the Enter the object names to select box, type the user or group name to which you want to assign the user right, and then click OK.