Symptoms

1. You are trying to install an agent
2. The installation fails with "Fatal error during installation"
3. When analyzing the installation log with MSI technology, you see the error "A null reference pointer was passed to the stub"
   
   Example of full error from msi log:

   1: MsiManagedMachineServiceInstall:Error 0xf50009: Failed to add existing user 'acronistest.local\acronisuser' to service users.
   | line: 0xd2c4f13c2d5bfd9e
   | file: d:\472\inst_supp\msi_supp\user.cpp:673
   | function: AddExistingUserToServiceUsers
   | $module: custom_actions_msp_vsa64_s_30988
   |
   | error 0xf50003: Failed to add user 'acronistest.local\acronisuser' to group 'SeServiceLogonRight'.
   | line: 0xd2c4f13c2d5bfb94
   | file: d:\472\inst_supp\msi_supp\user.cpp:151
   | function: `anonymous-namespace'::GrantUserPrivileges
   | $module: custom_actions_msp_vsa64_s_30988
   |
   | error 0xfff0: A null reference pointer was passed to the stub
   | line: 0xbd28fdbd64edb8f8
   | file: d:\472\core\common\error.cpp:314
   | function: Common::Error::AddWindowsError
   | code: 0x800706f4
   | $module: custom_actions_msp_vsa64_s_30988 

    

Cause

The mentioned user doesn't have enough rights on the affected machine.

Solution

To resolve the issue, manually add the user to the group 'Backup Operators':

1. Click Search, type in compmgmt.msc and press Enter.
2. Computer Management opens. Navigate to Local Users and Groups, click Groups, then double-click Backup Operators on in the right hand side.
3. In the Properties window, click Add.
4. In Enter the object names to select, type the affected user' username and click Check names.
5. Click OK and save changes.

For more information, check this Acronis Article

More information

If the suggested solution didn't resolve the issue, follow the instructions in the article: Required managed machine service user rights