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</p>
<p>Corruption of files may be rare, but not impossible. They could happen as a result of virus/malware infections, failing hard drives, RAM going bad/dust in RAM slots*, etc. </p>
<ul>
<li>Actually had several recent cases of this with some client machines. In such cases, blowing dust out of the RAM slots or replacing the bad RAM cards fixed the issue.</li>
</ul>