Create Large File to Full Disk Space

Quickly create large file on a Windows system

How do I make a large dummy file?

4 ways to create random dummy files with a specific size in...

Create a dummy file with the fsutil command.

Create a random dummy file with Dummy File Creator.

Create a random dummy file with Disk Tools.

Create a random dummy file with PowerShell.

Fsutil.exe is a built in filesystem tool that is useful to do file system related operations from command line. We can create a file of required size using this tool.

syntax to create a file:

fsutil file createnew filename length

(length is in bytes)

For example, to create a dummy file test.txt, with size as 50MB :

fsutil file createnew test.txt 52428800

AND THE TRICK IS THAT

When running fsutil file createnew if u save the extension as %random% it will duplicate itself like crazy. For example one place to save this without needing admin rights is the public pictures folder. Here’s just a line of my code

:loop
Fsutil file createnew d:\full\hugefile.%random% 52428800
goto loop

:loop will create infinite loop until disk fill

%random% will create random file extensions to distinguish between duplicate files

52428800 is file size in bytes ( can be enhance on mb and gbs but need to give in bytes, can be calculated on google)

fsutil will create hugefile.%random% in D: drive in full name folder

This will create many of these files quickly. Fill a hard drive in seconds.

For example, to create a 1MB (Windows MB or MiB) file named 'test', this code can be used.

fsutil file createnew test 1048576

fsutil requires administrative privileges though.

Unfortunately the FSUTIL creates files with nothing in them (seems like FSUTIL just marks the drive space as used with a content length of zero), so it isn’t of much use when we want to test the compression options of a backup system.