After running "C:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\Tools\dbvalidator.bat".
Inside "C:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\tomcat\logs\dbvalidator.log"
You can see that the database (SQL Server or Embedded) contains broken links to one or more policies.
2017-04-12 16:48:16.889 THREAD 1 AVERTISSEMENT: *********************************************
2017-04-12 16:48:16.904 THREAD 1 AVERTISSEMENT: Following ids are not present in the database.
2017-04-12 16:48:16.904 THREAD 1 AVERTISSEMENT: *********************************************
2017-04-12 16:48:16.904 THREAD 1 AVERTISSEMENT: Link is broken for [1] target ids :
2017-04-12 16:48:16.904 THREAD 1 AVERTISSEMENT: TargetId:[B797BEA1AC10020B01B8A6B81FE62478] TargetType:[MacAdminDefinedScan] ObjectTypeName:[ObjReference] ParentObjectTypeName :[MacAvScanPolicy] Parent's TopLevelObject's GUID:[C339F713AC10020B00FF50DAED853C17]
2017-04-12 16:48:16.951 THREAD 1 AVERTISSEMENT: <?xml version="1.0" encoding="UTF-8"?><AvPolicy Enable="1" Id="C339F713AC10020B00FF50DAED853C17" Name="Politique Antivirus" Description="XXX"
Delete the policy, corresponding to the "name=" tag seen inside dbvalidator.log, from Endpoint Protection Manager.
Then recreate the policy manually and reassign it to the same group(s).