Unable to Start User Profile Synchronization Service

Recently I was at a customer site and ran into an issue with the User Profile Synchronization Service failing to start. We found the following error in the SharePoint ULS logs: UserProfileApplication.SynchronizeMIIS: Failed to configure MIIS post database, will attempt during next rerun. Exception: System.Runtime.InteropServices.SEHException (0x80004005): External component has thrown an exception The problem ended up…

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