How to get product key of old OS (Win 7) after upgrading to Win 10?

Kari · 09 Oct 2015

OK, the video has to wait until tomorrow. Insomniac or not, I will not promise I will get it done tonight. Check the first screenshot in my previous post, lower third in the middle under the word Status; I did not notice that the time shown remaining was only for the first pass out of two. The Microsoft Expression Encoder now started the pass two showing over 6 hours remaining:

How to get product key of old OS (Win 7) after upgrading to Win 10?-2015_10_09_20_25_211.png

The reason the encoding takes so long is the length and quality of the raw video and my ailing hardware; I decided not to pause / cut the video to avoid any suspicions of foul play. In final editing I can speed it up when nothing is happening but I will not cut the video shorter.

NavyLCDR · 09 Oct 2015

Kari said:

The process as I did it:

Install Windows 8.1 Pro on a new machine, activate with a valid product key which had never been used before. A totally virgin key. Activation OK
Reinstall 8.1 Pro on same machine wiping the HDD, use the same key to activate. Activation OK
Reinstall 8.1 Pro on a new machine, use the same key to activate. Activation OK
Upgrade the last install to Windows 10. Windows 10 activation OK
Reinstall 8.1 Pro on a new machine trying to use the same retail product key, resulting this:

An erroneous experiment being used to prove an erroneous theory. Classic. You introduced a variable not being tested into the experiment - to wit, the repetitive use of the product key to activate different computers in a short period of time. You want a valid experiment? Take a computer that was upgraded on August 1-5 and do a clean install of the previous OS on it using the original product key used to upgrade it to Windows 10.

NavyLCDR said:

Now run slui 4 from a command prompt and attempt phone activation. You probably hit the online activation limit using the same key so many times in a short period of time.

Still an unanswered challenge. Was the product key blocked from online activation only because you used it too many times in too short of a period? Or is it blocked from phone activation as well, where you tell the computer voice you have it installed on only one computer?

Kari said:

No tutorial is needed, Microsoft has made this so clear there's no doubt: when an upgrade to 10 is made from a qualifying OS, the underlying valid product key is used to activate 10. It will be flagged as used, a free upgrade to 10 does naturally not give you two activated operating systems, the underlying and the new one. Only one OS will be valid, the upgraded 10, its activation based on the valid underlying product key.

Prove it. Here is the contrary to your claim:
Recovery options in Windows 10 - Windows Help

If go back isn't available

Check to see if you can restore your PC to factory settings. This will reinstall the version of Windows that came with your PC and remove personal files, apps and drivers you installed, and any changes you made to settings. Go to Settings > Update & security > Recovery > Reset this PC > Get started and look for Restore factory settings.

If you have installation media and a product key for your previous version of Windows, you can use them to go back. Get the details in the Use installation media to reinstall Windows section of this topic.

That is what Microsoft has really published. Have a nice day. (Or I guess night, there)

Kari · 09 Oct 2015

NavyLCDR said:

An erroneous experiment being used to prove an erroneous theory. Classic. You introduced a variable not being tested into the experiment - to wit, the repetitive use of the product key to activate different computers in a short period of time. You want a valid experiment? Take a computer that was upgraded on August 1-5 and do a clean install of the previous OS on it using the original product key used to upgrade it to Windows 10.

You are saying that it's just a coincidence that in this rapid test now, the first three activations were OK but as soon as I had upgraded to 10 the key would no longer work?

Previously, I have spoken out of my own long time experience. For instance, an activated retail Windows 7 Ultimate upgraded to Windows 10 the day Windows was launched, July 29th, the product key was used maybe in 4 or 5 Windows 7 activations before the upgrade during the past about 5 years I had it. Never an issue with activation, last Windows 7 activation was done sometime in March or April this year.

Trying to use that key now late September did no longer work. A valid retail key, only difference being this time it was used to upgrade to 10, and that the 30 day grace period to go back to old OS was gone.

NavyLCDR said:

Prove it. Here is the contrary to your claim:
Recovery options in Windows 10 - Windows Help
That is what Microsoft has really published. Have a nice day. (Or I guess night, there)

You cannot be serious! Only thing on that page having even remotely something to do with the topic in question is highlighted in the screenshot below:

How to get product key of old OS (Win 7) after upgrading to Win 10?-2015_10_09_20_52_271.png

That is obvious! Of course your underlying product key will again be valid and you can use your original OS if you decide to go back to your old OS. The thing is, your Windows 10 will in that case be no longer valid and activated.

I have paid for my lessons here, learned that there are members who do not tolerate being corrected. My mistake, I don't always remember the lessons taken. Sorry.

NavyLCDR · 09 Oct 2015

Kari said:

I have paid for my lessons here, learned that there are members who do not tolerate being corrected. My mistake, I don't always remember the lessons taken. Sorry.

You are correct, you do not tolerate being corrected.

Kari said:

That is obvious! Of course your underlying product key will again be valid and you can use your original OS if you decide to go back to your old OS. The thing is, your Windows 10 will in that case be no longer valid and activated.

That was the EXACT situation the OP was asking about when you posted your nonsensical statement that said it wouldn't do the OP any good to retrieve the previous OS product key. The the above statement is incorrect anyway, the Windows 10 will remain activated, if it remains installed, and the previous OS Product Key is used to reinstall the previous OS in a dual boot situation. Many members of this forum have done exactly that and both their Windows 10 and their previous OS on a separate partition are activated - although in violation of the EULA.

Joergi · 09 Oct 2015

To come back to the original question: After the upgrade to Windows 10, you have a 30 day period to go back to the previous version of Windows. The question now was whether - after these 30 days were over (and the previous version had been removed from the PC) and if you then went back to the previous version, if then this old version would still (meaning: again) activate.

The answer is: Yes, the old version of Windows will activate again. The old key can stil be used for the old version:

If you have installation media and a product key for your previous version of Windows, you can use them to go back. Get the details in the Use installation media to reinstall Windows section of this topic.

From Recovery options in Windows 10 - Windows Help, section "Go back to your previous version of Windows"

alphanumeric · 10 Oct 2015

Just started a clean install of Windows 8.1 Pro on a PC the had done the free upgrade to 10 Pro. 8.1 was originally installed with one of my MSDN keys. Several clean installs were done on that PC with that key before the upgrade to 10 Pro. My key is entered via a PID.txt file during the install. It's at the copying files part right now. Key has already been read as far as I know. Will have to wait for it to finish and look at the system screen.

alphanumeric · 10 Oct 2015

Ok install finished system page shows "Windows is activated" as I knew it would. I don't know what Kari is doing to mess up activation, but I had no problem going back to 8.1 Pro from 10 Pro. That 8.1 pro key was well used too, only ever used on that one PC though. I've seen several other threads where people have gone back to the previous OS via a clean install with no issues also. Other than finding the correct install media that is.

NavyLCDR · 10 Oct 2015

alphanumeric said:

I don't know what Kari is doing to mess up activation, but I had no problem going back to 8.1 Pro from 10 Pro.

Reusing the same product key in a short period of time across multiple computers will get that product key banned from online activation, but it can still be used for phone activation. In my days of beta testing Windows I had product keys that were blocked from online activation but could be used with phone activation. Then after about 6 months of non-use, the product key would activate online again.

alphanumeric · 10 Oct 2015

Anyway, to get back on track. As mentioned, OEM keys are not stored in the BIOS for factory Windows 7 OEM installs. All that is in the BIOS is an OEM marker in the SLIC table. Even if you retrieve the OEM key from the Windows registry, its useless without the matching OEM install media that has the certificate file on it. Try to use it with normal install media and it will fail activation. You can't phone activate that key either. You need the key on the COA sticker to do a clean install with normal non OEM install media. If the Windows 7 install has been wiped by a clean install of a new OS, so has the key that went with it, OEM or not.

alphanumeric · 10 Oct 2015

NavyLCDR said:

Reusing the same product key in a short period of time across multiple computers will get that product key banned from online activation, but it can still be used for phone activation. In my days of beta testing Windows I had product keys that were blocked from online activation but could be used with phone activation. Then after about 6 months of non-use, the product key would activate online again.

Yeah, I'm very careful to keep track of what keys get used on what PC. Windows and office etc. I've done a bunch of clean installs with my MSDN keys with absolutely no issues.