The File Replication Service could not grant an unknown user access to the API "%1". Access checks can be disabled for "%1" ...

Windows Server 2003

The File Replication Service could not grant an unknown user access to the  API "%1".  
  
Access checks can be disabled for "%1" by running regedt32.  
  
Click on Start, Run, and type regedt32.  
  
Click on the window entitled HKEY_LOCAL_MACHINE. Double click on SYSTEM,  CurrentControlSet, Services, NtFrs, Parameters, Access Checks, "%1", and "%2".  Change the string to Disabled.  
  
Permissions can be changed by highlighting "%1" and then clicking on the  toolbar option Security and then Permissions...

The file replication service cannot satisfy the request because the user has insufficient privileges. The event log may have ... The File Replication Service cannot start replica set %1 on computer %2 for directory %3 because the type of volume %4 is ... The file replication service cannot stop replicating the system volume because of an internal error. The event log may have ... The File Replication Service could not grant an unknown user access to the API "%1". Access checks can be disabled for "%1" ... The File Replication Service could not grant an unknown user access to the API "%1". Access checks can be disabled for "%1" ... The File Replication Service could not prepare the root directory %1 for replication. This is likely due to a problem creating ... The File Replication Service detected an invalid parameter value in the registry. %1. The expected registry key name is "%2". ... The File Replication Service detected an invalid parameter value in the registry. %1. The expected registry key name is "%2". ... The File Replication Service did not grant the user "%3" access to the API "%1". Permissions for "%1" can be changed by running ...