Checking ISO downloads with CRCutility

When dowloading ISO files from Microsoft or other vendors, it is recommended that you verify that the download was successful and that no corruption occurred in the process. Especially as we are now most often downloading DVD size files.

You can use a free utility to calculate a checksum against the file(s) downloaded, and compare it to the published, calculated checksum from the vendor. If you don’t already have a checksum utility, you can download a free, DOS command line checksum utility here: The FSUM utility allows you to calculate a checksum using any of the standard methodologies, such as MD5 and CRC-32.

Here’s an example I recently ran using the FSUM utility:

I downloaded a 4gb .iso file from a vendor site. The vendor included on their web site what the calculated CRC-32 checksum should be: 0xBD290784.

After downloading the .iso file to the TEMP folder on my computer, I ran the following from a DOS command prompt:
C:\TEMP\fsum -crc32 Beta1_DVD1.iso

And here is the resul I received back in about one minute:

SlavaSoft Optimizing Checksum Utility – fsum 2.52.00337
Implemented using SlavaSoft QuickHash Library <>
Copyright (C) SlavaSoft Inc. 1999-2007. All rights reserved.

; SlavaSoft Optimizing Checksum Utility – fsum 2.52.00337 <>
; Generated on 05/19/07 at 08:30:04
bd290784 ?CRC32*Beta1_DVD1.iso

Note that the checksum (bd290784) matches. I’m all set to proceed!

One thought on “Checking ISO downloads with CRCutility

  1. Great! I’m glad the iso was not corrupted. What’s the next step if there’s not a match with the checksum?

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