Finally, Windows Update will temporarily disable hiberfile.sys, pagefile.sys, and other system files in order to use the space these files typically consume to apply the feature update. Any files that are disabled to apply the update will be automatically re-enabled when the update is complete. Because these files vary in size depending on how you use your PC and the amount of RAM your PC has, even in cases where two different PCs have the exact same OS image, the amount of free disk space required to complete an update may vary.