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

Build 3683:
[Unknown since I didn't use it, but if somebody else has the information, then feel free to provide it.]

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

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

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

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

These CRC 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 <ISOFilename>). 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.

Thanks to IEXBETA for the information.