ESENT.dll is part of Microsoft's Extensible Storage Engine It's responsible for Defragmentation, Recovery, Integrity, Checksum, Repair, etc of Storage Volumes. It could be that the scheduled defrag that Windows runs is triggering, or something else to do with your storage volumes. Or it could also be some other corruption. Before troubleshooting this issue I would do all of the following: 1) Update your chipset drivers for your motherboard to the latest version (if you need help with this please post what motherboard you are using) 2) Update your USB drivers if they are separate from 1 3) Check the task scheduler \Microsoft\Windows\Defrag\ScheduleDefrag task, look at it's History tab, has it been failing regularly? You may also want to check \Microsoft\Windows\Data Integrity Scan for similar issues. 4) Related to 3, does this error occur often when the system is idle (therefore the scheduled defrag is allowed to run)? 5) Run "chkdsk C: /f /r" (you'll be prompted to reboot, and this will take awhile but it'll eliminate errors that could be caused by file system corruption) 6) Run a "sfc /scannow" Options 5 and 6 will be need to be ran at an Administrative Command Prompt. Post back results for further assistance!