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Installing the 64-bit version on a 32-bit system will result in a failure error (often 0x8007000D or "The update is not applicable to your computer"). Conversely, installing the 32-bit version on a 64-bit OS will usually fail the prerequisite checks because the OS expects 64-bit binaries for system files located in the System32 directory, which 32-bit installers do not target correctly.

[01]: KB2533