File Sizes and CRC Values of Builds,
Look here to verify your ISO download.
[Last Updated on April 28, 2004]

This information is provided to help you verify that your download of an ISO file for a Longhorn build is not corrupt.

Build 3683 (Betas original):
- File Size = 529 MB (555,421,696 bytes)
- CRC Value = 0x691DCE9B {Variation #1}
^ According to Betaguy9000. Thanks.
- CRC Value = 0xDA96240B {Variation #2}
^ According to horvath and confirmed by me. Thanks.

Build 3683 (with Werejag's bootable CD fix):
- File Size = 573 MB (600,844,288 bytes)
- CRC Value = 0x8035F855

Build 3718 (iNFLUENCE original):
- File Size = 511 MB (535,867,392 bytes)
- CRC Value = 0xCADF1F2A
^ According to EmoAddict15 and confirmed by me. Thanks.

Build 4008 (WinBeta original):
- File Size = 655 MB (687,116,288 bytes)
- CRC Value = 0xB3EF7A4C

Build 4015 (WinBeta original):
- File Size = 668 MB (700,616,704 bytes)
- CRC Value = 0xD41D6A48

Build 4015 (with Winbeta's bootable CD fix):
- File Size = 665 MB (698,259,456 bytes)
- CRC Value = 0xC9EF215F
^ However, ReflectiaX's fix is ten times better and it completely works. :-p

Build 4015 (with ReflectiaX's bootable CD fix):
- File Size = 665 MB (698,214,400 bytes)
- CRC Value = 0x8F6E9A57

Build 4029 (original):
- File Size = 687 MB (721,195,008 bytes)
- CRC Value = 0xF8C419C6
^ According to JoePacton and confirmed by me. Thanks.

Build 4051 (MSDN/PDC original):
- File Size = 694 MB (710,994 KB)
- CRC Value = 0xC9E08BF9
^ According to candyman123.

Build 4051 (WinBeta original):
Size = 659 MB (691,961,856 bytes)
CRC = 0x95220E35
^ According to Quantum Topology and confirmed by me. Thanks.

Build 4051 (with XBeta's fix pack):
- File Size = 660.10 MB (692,168,704 Bytes)
- CRC Value = 0xACDD8847
^ According to Jay16K. Thanks.

Build 4051 (with Betas' fix pack):
- File Size = 659 MB (691,853,312 bytes)
- CRC Value = 0xA51781C0

Build 4051 (with ReflectiaX's fix pack):
- File Size = 659 MB (691,867,648 bytes)
- CRC Value = 0xDF346283
^ According to Betaguy9000 and confirmed by me. Thanks.

Build 4051 (as mstest's "Lite Edition" with i386 folders):
- File Size: 585 MB (613,822,464 bytes)
- CRC Value: 0x900C5F9B
^ According to slammy_dunken. Thanks.

Build 4053 (BetasIRC original):
- File Size = 676 MB (708,933,632 bytes)
- CRC Value = 0xBB1F1B3F
^ According to candyman123. Thanks.

Build 4053 (WinBeta Proper version):
- File Size = 676 MB (708,943,872 bytes)
- CRC Value = 0xBD9DEF90
^ According to slammy_dunken. Thanks.

Build 4053 (with Flexbeta's bootable CD fix):
- File Size = n/a
- CRC Value = n/a

Build 4074 (MSDN/WinHEC original):
- File Size = n/a
- CRC Value = n/a

Build 4074 (with Betas original):
- File Size = 733 MB (769,388,544 bytes)
- CRC Value = 0xF0464B61

Build 4074 (with ReflectiaX's fix pack):
- File Size = 732 MB (768,567,296 bytes)
- CRC Value = 0x7144695C


NOTE: Unless otherwise stated, the CRC values for all of the "fixed" builds are based on ISO files that were re-generated using the ISO9660 file system and NOT the Joliet file system!


Of course, as more builds come out in the future, I'll go back and update this page accordingly.

These CRC (Cyclic Redundancy Check) values were generated using Microsoft's CRC Verification Utility v3.00 which can be downloaded from here. If someone else wishes to mirror the download, then be my guest.

To generate your value, place a copy of the previously mentioned EXE beside the ISO, open a Command Prompt, change to that location (i.e. cd downloads), and run the utility providing it the name of the file (i.e. crc ). Afterwards it will report the resulting CRC value which you can then compare to the ones above. It will also tell you if your download is outright corrupt.


Hope it helps and here's to the future of Longhorn!