Legacy Backup API Failing on HrESEBackupReadFile with HR=0xC7FF1004

Recently I had the opportunity to dig into an interesting failure with the Exchange Legacy Backup API (ESEBCLI2.DLL).  A backup vendor was seeing a reproducible error when they tried to remotely backup certain Exchange servers from their backup software when running on Windows Server 2008.  They found that their call to HrESEBackupReadFile was returning 0xC7FF1004…

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