Extending Active Directory schema Failed in Exchange Server 2010 with error code is: 8224, Exchange Server setup encountered an error.
The following error was generated when "$error.Clear();
install-ExchangeSchema -LdapFileName ($roleInstallPath + "Setup\Data\"+$RoleSchemaPrefix + "schema0.ldf")
" was run: "There was an error while running 'ldifde.exe' to import the schema file 'C:\Windows\Temp\ExchangeSetup\Setup
\Data\PostWindows2003_schema0.ldf'. The error code is: 8224. More details can be found in the error file: 'C:\Users\laba
The Exchange Server setup operation didn't complete. More details can be found in ExchangeSetup.log located in the
Exchange Server setup encountered an error.
This issue happens when there is a problem in AD replication between 2 Ad sites, I had firewall enabled between the AD sites, after disabling the firewall I was able to extend the schem.