What is Prefetch, and should you delete the folder?

What does Prefetch do?

Windows uses earlier read patterns to prepare data for startup. Prefetch files normally live in C:\Windows\Prefetch. They hold information about application launches and the files involved; they are not another installation of each program.

Sources: Microsoft Learn: Improving System Startup Performance · Microsoft Incident Response: Prefetch (PDF)

Does clearing it make Windows faster?

Our practical recommendation: information intended to reduce repeated work should not be part of an automatic “delete everything” routine. Once removed, it is initially unavailable for the next launch. That does not establish a lasting speed improvement.

If your drive is full, measure folder sizes first. Compare Prefetch with videos, downloads and old backups. A small Windows helper file is rarely a worthwhile target for system changes. For a specific startup problem, investigate the application involved.

Is the value in its filename a security check?

The short value in a Prefetch filename relates to the executable path and, in some cases, launch parameters. It is not a SHA-256 checksum of the downloaded program. A familiar filename also does not establish that a file is safe.

Sources: Microsoft Incident Response: Prefetch (PDF)

Find more useful cleanup targets

1. Compare sizes

   Scan the drive with DiscReveal and follow the largest folders. It shows sizes without automatically deciding what to delete.

2. Start with your own files

   Review large files whose purpose you understand. Old video exports or deliberately retained archives are easier to assess than internal Windows startup data.

3. Use Windows storage management

   For temporary Windows files, start with Windows storage settings. Read the selected categories before confirming cleanup.

Sources: Microsoft Support: Storage Sense