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After you install Microsoft Exchange Server 2013 Service Pack 1 (SP1) or you upgrade an existing Microsoft Exchange Server 2013 installation to Exchange Server 2013 SP1, third-party or custom-developed transport agents cannot be installed correctly.
Additionally, the Microsoft Exchange Transport service (MSExchangeTransport.exe) cannot start automatically. Specifically, you cannot enable third-party products that rely on transport agents. For example, you cannot enable anti-malware software or custom-developed transport agents.
Products experiencing the issue are:
- TrendMicro ScanMail
- McAfee Email Security (GroupShield)
- Symantec Mail Security for Exchange
- AVG for Servers
- ESET Mail Security for Exchange
- CodeTwo Exchange Rules
This problem occurs because the global assembly cache (GAC) policy configuration files contain invalid XML code.
Microsoft published article about this issue KB2938053 where you can download script which will repair xml files Exchange2013-KB2938053-FixIt.zip.
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