What Is a Windows Prefetch PF File? Contents, Analysis, and Deletion

A .pf file in C:\Windows\Prefetch is a Windows Prefetch record. Windows uses Prefetch information to prepare data needed when the system or an application starts, and the file can also contain useful clues such as an executable name and recorded run times. A PF file does not, by itself, identify who launched a program, what they did in it, or whether the program is safe.

What is the Prefetch folder for?

Prefetching uses earlier data-access patterns to load data before it is requested again. Microsoft describes prefetching memory pages as one of the techniques Windows uses to reduce startup time. PF files support this process; they are not documents that a person normally opens and edits.

The usual location is C:\Windows\Prefetch. You can enter that path in File Explorer's address bar to inspect the folder. Windows may ask for permission to open it. A missing PF file for a particular application does not establish that the application has never run: the available records depend on the machine's configuration and what files have been retained.

What information can a PF file contain?

The layout varies by Windows version. The libscca Prefetch format documentation describes fields for the executable name, run count, recent run times, referenced file paths, and volume information. Recent Windows versions may store PF data in compressed form, so opening a file in Notepad usually produces unreadable characters rather than a useful report.

A typical name looks like PROGRAM.EXE-12345678.pf: an executable name followed by a Prefetch hash. That hash helps identify the record; it is not an antivirus verdict or a digital signature. An unfamiliar name warrants further checking, but it is not proof of malware.

How to read a PF file

File Explorer can show the filename and basic properties, but you need a parser to read the fields inside. One option is the PECmd project, which accepts either one PF file or a directory. Download tools from their official source. Because PF files can expose software-use and file-path information, avoid uploading a file from your PC to an untrusted online parser.

1. Open C:\Windows\Prefetch in File Explorer and locate the PF file you want to inspect. Keep the original unchanged while investigating it.
2. Prepare PECmd, then run the command below in a terminal. Replace the example filename with the actual one. Run the command from the folder containing PECmd.exe, or specify its full path.

PECmd.exe -f "C:\Windows\Prefetch\PROGRAM.EXE-12345678.pf"

To process the whole folder, use the directory option instead. Both command forms are documented in the PECmd usage examples.

PECmd.exe -d "C:\Windows\Prefetch"

Review the reported run count, timestamps, and paths together rather than treating any one field as conclusive. PF timestamps are stored as UTC-based Windows FILETIME values; check whether your tool displays UTC or converts them to local time. A parser that does not support the particular PF format version may omit fields or misread the file.

Should you delete PF files?

There is usually no reason to clear the Prefetch folder as routine maintenance. Removing a PF file discards a performance record that Windows may create again when needed. It does not uninstall the associated application or check that application for malware. If you are troubleshooting a storage or startup issue, identify the actual cause before removing system records.

PF evidence also has limits in both directions. The absence of a file is not proof that a program never ran, because records may not have been created or may no longer be present. The presence of a file does not prove who initiated a run, why it happened, or what the program did afterward. For a security investigation, consider PF data alongside other logs and the original executable.