I think External Event is What We Are All Afraid Of: when the system must be rebooted, softly or hardly. The cache and temp data is lost, the heavily imprinted

I think External Event is What We Are All Afraid Of: when the system must be rebooted, softly or hardly. The cache and temp data is lost, the heavily imprinted / written data persists, and the function remains the same but probably some bugs fixed.