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Question

Question

Why is the hardware fingerprint changing in a Windows Hyper-V guest VM?

asked on February 12, 2015

I run a Windows 8.1 Hyper-V guest VM for my demos with our VAR kit installed. I've never had problems until demoing at a new prospect. Two demos in a row have started with me waking my laptop from sleep to discover that the license was invalid, requiring a very awkward 5 minute pause while I manually reactivated my VAR kit.

The first time I thought it was Windows updates in the VM that did it but after it never recurred and I disabled automatic updates I thought I had it. Other demos and training sessions went fine. I worked day in and day out for weeks on my laptop with reboots and so on with no problem. Then I went and did a second demo with the same customer and had exactly the same result. I had carefully tested hibernating the VM because I didn't want the same thing to occur. My tests in the morning went perfectly but when I arrived at the customer the exact same deactivation happened. I wasn't even connected to their network, only plugged VGA output into their flat panel.

I always thought the HWFP is based on the base system components and the NIC.. I have the NIC MAC set to static so it's not the MAC that's changing. Ideas?

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Replies

replied on February 12, 2015

I would recommend try asking in the Microsoft forum, as they will have more experience with Microsoft products.

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replied on March 31, 2015

So hardware fingerprint is a Microsoft function? I thought that it was a Laserfiche hash. I ask because it just happened again to me on the same VM.

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replied on April 1, 2015

I believe what Tommy meant is that Microsoft might be able to better explain why hardware information is changing.

The hardware fingerprint is, as the name implies, tied to the hardware of the machine. The algorithm for determining the fingerprint is consistent, so if the fingerprint is changing, it implies that the information the algorithm sees regarding the hardware is changing.

If this issue is regularly reproducible (and it sounds like it is), I would make note of the hardware fingerprint before and after the issue occurs, then open a support case to help determine what exactly might be triggering the mismatch. It is odd that it's only occurring when visiting this specific site.

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replied on September 28, 2015

Last Weekend we applied the most recent Windows updates for Server 2012 and our license file was invalidated because the HWFP changed.  I understand that it is supposed to be about the HWFP, however, I have seen this now about 3 times where the client says that only thing that changes was we applied Windows/Server updates and then after rebooting LF would not restart.  And it was because the fingerprint in the lf.licx file does not match what the ShowHWFP utility shows.  So we have to deactivate and reactivate so it captures the current HWFP.  Has any one else experienced this lately and was anyone able to find any information from Microsoft about this?

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replied on September 28, 2015

Microsoft probably won't be able to help unless you talk to LF support first to determine what is triggering the mismatch (then, they may have information about why it changed). To my knowledge, no support case was opened for this post, so no information about the issue was be gathered. If you have the new and old HWFP, you could try opening a support case to see if we can determine what's going on.

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replied on September 29, 2015

So the main reason that no Support case was opened is because in the Event viewer it told me that the HWFP did not match, so with our knowledge of LF we were able to simply recreate the license file and resolve the issue on our own.  The reason I have posted is because over the past couple of months, I have seen this happen to about 2 other clients and then happen on our system, so I was just trying to see if other VAR's/Clients out there have had this happen to them lately.

Thanks

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replied on February 28, 2017 Show version history

I ran into a similar issue. I had to be connected to the WIFI before starting the server within Hyper-V. Otherwise, the HOST ID, which you set as static, will change causing the HWFP to change.

 

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replied on January 8, 2018

I have a few clients running into similar issues. They have the MAC addresses 'locked' on their Hyper-V virtual machines, but the HWFP has changed after patching and a restart. 

Has anyone made any additional discoveries about this problem in the last year or so?

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