Primary question - What is the sha1 {&/or Md5} checksum for the "windows.ISO" file downloaded when using the MS supplied "mediacreationtools.exe"? I specifically want the checksum for the ISO resulting from selecting Language: English {UK} Edition: Windows 8.1 Architecture: 64-bit {x64}

Situation - I am wanting to do a clean install of win 8.1 {build9600} onto a laptop which has a barely usable build 9600 already installed, damaged recovery partitions, and no OEM recovery media.

I have downloaded and used the Microsoft supplied tool 'mediacreationtool.exe' which subsequently downloads a file called 'Windows.iso'. I wish to verify the integrity of that ISO file to ensure it arrived correctly. Obviously I want to do that **before** I repartition the HD and attempt to re-install OS rather than simply cross my fingers and hope all goes well.

I have searched for a checksum or other method to ensure the ISO is 'good' yet could not find one.

I downloaded a second copy of the same type of ISO using the same method with the same tool. I had hoped for the same checksum on both ISOs as a means of verification.

If the 'media creation tool' uses an 'automatic' checksumming/correction as part of the download process to ensure the integrity of the downloaded ISO then it appears to be untrustworthy given that the two ISOs it gave me, which should have been the same, unfortunately arrived with different checksums.

It is obviously ludicrous to continue downloading >3GB files until I find a pair whose checksum match. I am frustrated by this situation.

I presume Microsoftland employs at least a few brainiacs who are capable of  understanding what checksums are and how they can be useful. Consequently I am astounded that MS does not publish the checksums for ISOs officially obtained from MS, using an official MS tool. Can anyone shed some light on why this situation exists and offer a useful remedy?

• Edited by Yisit Sunday, March 22, 2015 3:55 PM

Hi Shaon. Thankyou for your response.

It appears to be that the MSDN site you provided a link to *cannot* provide a checksum for my needs because it does not provide any single edition 'Core' ISOs at all.

Perhaps Shaon I am missing a significant bit of knowledge which should firstly be established. Is a consistent checksum even possible when using the official MS 'Windows Installation Media Creation Tool'?  The mystifying absence of verifying checksums, by both MS and users alike, begs this question.

Eg, If customer "A" in England used the 'Media Creation Tool' to download the ISO for the UK language, 64-bit 'regular' {ie. non-"N", non-"Single-Language"} 'Core' edition of win8.1 and then hashed the resulting ISO can customer "B" in Australia, using the same tool to download the same product, expect to receive the same ISO with the same checksum ?

If Yes, where can I *really* find these common checksums ?

If No, what might be the differences between the ISOs received by customers "A" and "B" which would lead to different checksums and how might these differences affect the integrity of any files within the ISO ?

Whilst I am miffed by the 'need' created for any sort of workaround,  I thankyou Shaon for your advice re testing the ISOs in a VM or on another system. I wasn't able to test with a VM yet I could do so the 'old fashioned way'.

My first DVD failed to boot. Later on I could reasonably say this resulted from a "known bad" download.

My second DVD made from the other ISO managed to complete the setup. This surprised me greatly because I had witnessed the internet connection fall over during the download of that ISO. Whether it can also successfully install on a UEFI machine such as it's intended target remains to be tested.

Whist the outcome is ostensibly sufficient I nonetheless feel like an accountant who has ended up with more cash than listed in the books - I can't yet trust the process. The MS tool gave me one  bad download yet *zero* indication of any failure. How can I be *certain* that the other ISO is not corrupted in any way ?

You say we "could know if it is completely downloaded" using this 'suck it and see method'. Given that the second ISO resulted in the ability to install the OS does this **absolutely guarantee** the integrity of the ISO and of every file within it or does it merely indicate that the files are "probably" OK ?

'Best practice' dictates I verify the file is true before moving forward. Doing this seems to be especially pertinent given the 'troubled' driver environment which, according to the countless first hand accounts I have stumbled across, has followed the introduction of win8.1update1 {aka "win9"}. If there's a rattle or a groan after I start loading drivers I don't want to - and shouldn't have to - look backwards and wonder if the root cause is a dodgy system file resulting from corrupted install media.

The sha1 Checksum for the UK English, x64, Core 'windows.iso' I have is --

d81aea693dd977059c924d81e18a4dc1b2cc9071

What's yours?

• Edited by Yisit Tuesday, March 24, 2015 10:34 PM

Like Yisit, I assumed that the "mediacreationtool.exe" was just downloading the ISO. That explains why my checksums aren't matching for the same ISO downloaded multiple times.

I've discovered that if you want the Windows 8.1 or Windows 10 ISOs that Microsoft displays checksums for on their TechNet site "http://technet.microsoft.com/en-us/subscriptions/downloads/", do the following:

1) Use a web browser on a Linux system (I used Firefox on OpenSUSE 13.2) and go to "http://www.microsoft.com/en-us/software-download/windows8iso" or "http://www.microsoft.com/en-us/software-download/windows10iso".

Note: I'm not sure if a Linux system is required but when I navigated to the URLs above on a Windows system, I got automatically redirected to "http://www.microsoft.com/en-us/software-download/windows8" or "http://www.microsoft.com/en-us/software-download/windows10" respectively where I was asked to download and run the 'mediacreationtool.exe'.

Windows 7 ISOs are also available, but I think you need a retail product key "http://www.microsoft.com/en-us/software-recovery".

2) Select the "region" edition of Windows 8.1 (e.g. K, N, Single Language - all ISOs come with Standard/Home and Pro) that you require and click confirm. Then select the language you require and click confirm. Note: TechNet does NOT provide checksums for Single Language "region" editions, for some reason.

3) Click to download the 32bit and/or 64bit ISO. The page claims that links will be valid for 24-hours.

So while you still can't verify Windows Single Language ISO checksums against Microsoft, at least you'll get consistent checksums. Hope this helps. Now that my account has been verified, I've added some images below. It seems like to get any decent paragraph separation you need to know HTML...

• Edited by BlueyThunder 7 hours 2 minutes ago