Build crashing when rift in standby mode

Hi guys,

I've been doing some testing with my new VR system and we've found that if I build the game, it will run fine as long as one wears the HMD, but if the HMD is taken off and left to sit there for some time (usually around a few minutes), the game will crash and produce the following error log message:

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Unity Player [version: Unity 5.4.0f3_a6d8d714de6f]

VirtualMechanic.exe caused an Access Violation (0xc0000005)
in module sys_build.exe at 0023:01323116.
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this...

Build crashing when rift in standby mode