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Can I freely alternate between Win 8 and Win10 forever?

brocks

Member
If you just want my question, it's this: as long as I use the same PC, will I be able to switch between Win8 and Win10 indefinitely (or at least as long as Win8 is supported), using only the free upgrade, without a new product key?

Background for the question, in case it doesn't make sense:

In case you didn't know, you don't need a product key to activate Windows 10, as long as you install it the first time by starting the Win10 setup from a genuine, activated version of Windows 8. That's what I did.

As I understand from internet articles, and as my experience seems to confirm, once you do that and connect to the internet, Microsoft makes some kind of hash from your hardware and stores it on its servers. You can then do a clean install of Win10 on a bare drive, without entering any product keys, and once you connect to the internet, Microsoft will check to see if your hardware is already registered (it evidently doesn't care if you switch hard drives; it's looking at MB, video card, etc.) If it is, then it activates Win 10 for you as part of the setup, even though you did a clean install on a bare drive and didn't enter a key. I tried that with a brand new drive, and it works.

But I still have several drives that boot up with Win 8.1. I've always found it easier and faster to use separate drives with separate boot partitions instead of a multi-boot scheme. I have several physical drives, and of course my MB allows me to pick which drive to boot from, so I just restart my PC and point to a different drive to switch between Win 8 and Win 10. I want to keep using Win8 as my main OS, because everything is working the way I want on it, but I also want to keep using Win10 because it has some advantages, and I'll slowly migrate my programs and data over to it over the next year.

So, right now, I can boot from either a Win8 or a Win10 drive, and they both show up as activated. But I also heard on some radio show that Microsoft only allows you one month to switch back if you don't like Win10. I've searched online, but I get so many hits for very basic articles about upgrading to Win10 that I might as well just search on Windows.

So is it allowing me to switch back and forth now because I'm still inside one month, or will I be able to continue switching back and forth indefinitely? Thanks for any help, and links to credible sources will be especially appreciated.
 
But I also heard on some radio show that Microsoft only allows you one month to switch back if you don't like Win10.
I'm pretty sure they're talking about on the same drive, if you updated to Windows 10 from 7 or 8 on it. I don't think this applies to having two different OSes on different drives. I don't see how the Windows 10 drive can corrupt the Windows 8 drive, and I don't think a legitimate copy of Windows 8 will randomly stop working because knows you also use Windows 10, but you never know.
 
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Technically yes, you can.

The 30 day limit is how long Windows 10 retains your previous Windows version installation. After 30 days it deletes all that stuff, which means you'd have to reinstall the previous version from scratch.

If you're dual booting though this won't be an issue.
 
I'm pretty sure they're talking about on the same drive, if you updated to Windows 10 from 7 or 8 on it. I don't think this applies to having two different OSes on different drives. I don't see how the Windows 10 drive can corrupt the Windows 8 drive, and I don't think a legitimate copy of Windows 8 will randomly stop working because knows you also use Windows 10, but you never know.

I didn't think Win10 would corrupt the Win8 drive, but I thought they might check the hardware hash on the Win8 drive and see that it was the same as one that was already registered as Win10, and block one or the other. No reason they should, since I obviously can only run one at a time, but like you said, you never know.
 
Technically yes, you can.

The 30 day limit is how long Windows 10 retains your previous Windows version installation. After 30 days it deletes all that stuff, which means you'd have to reinstall the previous version from scratch.

If you're dual booting though this won't be an issue.

I have images of my Win8 drives, so I wouldn't have to reinstall it; I'd just restore it, unless Microsoft does something with my activation to prevent it. In any case, the first thing I did after I installed Win10 was delete the Windows.old folder, because it makes the backup image about 50% larger, so my previous version is already gone, at least from that drive.
 
I would recommend you at least remove the drive letter from the Win10 drive in the Windows 8 install and vice-versa. Call me paranoid but I do believe Win10 will mess with the other drive... 8 might do the same to the 10 drive.

My system has Windows 8.1 on what it sees as C drive and Windows 10 on what it sees as C drive. They are different physical drives. They each share Drives D and E (partitions on a 3rd drive). System seems to be happy this way and the two operating systems only cross trails at the bcd.
 
Technically yes, you can.

The 30 day limit is how long Windows 10 retains your previous Windows version installation. After 30 days it deletes all that stuff, which means you'd have to reinstall the previous version from scratch.

If you're dual booting though this won't be an issue.

This, I confirmed from Microsoft the upgrade will make your key technically both a Windows 7 or 8 / Windows 10 key but you can only have it activated on 1 computer at a time not both.
 
Wow, that's pretty bad.

Yeah, I was too mad to try and track down exactly what happened, but the Windows 10 refresh complained about user files being in two locations for the first option, leaving only the second option for a refresh, and sure enough when I booted into Win7 afterwards I got a message that a temporary user account had been created and had a user.old folder at the root of that drive. And the Win10 install was a fresh insider install, not an upgrade from the Win7 install, so it had absolutely no business mucking with that drive at all. Hell, I'm still mad over it.
 
This, I confirmed from Microsoft the upgrade will make your key technically both a Windows 7 or 8 / Windows 10 key but you can only have it activated on 1 computer at a time not both.

That is good news. I hope that means that if I get a new motherboard or something in the future, I can call MS and switch the key over, and still use both versions.
 
Win10 absolutely will mess with the other drive. I did a Win10 reset and it nuked my User folder on my Win7 install on another physical drive.

Yikes. I have booted Win10 with a Win8 drive (different physical drive) present without problems, but maybe the reset is different. And I don't remember exactly what happened, but a few years ago, Windows screwed up a drive that it should have left alone, so I absolutely believe you.

I also had a horrible experience with AOMEI's free Backupper 3 when I was installing Win10. I've been using AOMEI's Backupper and Partition Asst for a couple of years, and loved them -- free. intuitive, fast, and accurate. But when I upgraded from Backupper 2.5 to 3 a month ago, thinking that 3 must have been optimized for Win10, it somehow trashed my C drive (this was on a Win81 drive, because I hadn't installed Win10 yet). All I did was run the install, and it said it found an old version of Backupper, did I want to delete it?, and I said yes. It then said restart required, and when I restarted, my drive wouldn't boot. I booted from another drive, and found that the whole C: partition on the other drive was gone.

I should have stopped right there, but I figured it was just a fluke, so I went ahead and installed Win10 on a third drive, and then installed Backupper 3 to it. No problems, since there wasn't an old version of Backupper to delete on the new Win10 drive. Then I used Backupper to image the new Win10 system partition, again without problems, although I had to manually start VSS, which I never had to before.

Then I used Backupper 3 to restore the Win10 image to the partition that it had previously trashed on my Win8 drive. When it started the restore, I suddenly got a message from TrueCrypt that a drive had been forcibly dismounted, and I thought, uh-oh. The restore seemed to run without problems, but it evidently overwrote the first few MB of the neighboring partition, which just happened to be an encrypted partition over a terabyte long, and almost full. Some of it was backed up, but most of it wasn't. I'm pretty sure it's gone forever, since recovery tools won't work with an encrypted partition whose header is gone, but I'm not going to delete it until I spend a long time trying to figure out what happened, and how I can fix it.

The moral is, any time you use a new version of Windows, or any other program that messes with your partition table, test it thoroughly on test drives.
 
I had the experience once of Win7's installer hosing my D-colon drive. I had a 1TB WD Green drive as the OS drive in my HTPC at the time. I had it partitioned, with a primary for OS, and a secondary for data. I had need to re-install 7 for some reason, and after I did, the D-colon partition was gone. I did NOT choose to blow away the partitions manually, I know that much.
 
I had the experience once of Win7's installer hosing my D-colon drive. I had a 1TB WD Green drive as the OS drive in my HTPC at the time. I had it partitioned, with a primary for OS, and a secondary for data. I had need to re-install 7 for some reason, and after I did, the D-colon partition was gone. I did NOT choose to blow away the partitions manually, I know that much.

I won't get too critical, but you think a green drive might not have been a problem.

Those things aren't ripe yet 🙂

teasing a bit, kinda.
 
This brings up an interesting point. Using Microsoft's Tool, I downloaded Windows 10 as an ISO file. The tool even created a bootable DVD from it. I used that DVD to upgrade one of my Win 8.1 drives in my desktop. When all the dust settled, I was able to see a new Key ID using Belarc Advisor. It was different than the 8.1 key.

Then I used the same DVD to upgrade a Win 7 drive in my laptop (Lenovo T510.) That went well, but the same key ID that was in the desktop was also in the laptop. Both Win 10 installations were activated. That is two different machines - but both had the same key ID. That does not seem to track with MS's position as stated above.
 
This brings up an interesting point. Using Microsoft's Tool, I downloaded Windows 10 as an ISO file. The tool even created a bootable DVD from it. I used that DVD to upgrade one of my Win 8.1 drives in my desktop. When all the dust settled, I was able to see a new Key ID using Belarc Advisor. It was different than the 8.1 key.

Then I used the same DVD to upgrade a Win 7 drive in my laptop (Lenovo T510.) That went well, but the same key ID that was in the desktop was also in the laptop. Both Win 10 installations were activated. That is two different machines - but both had the same key ID. That does not seem to track with MS's position as stated above.

These tools only give you a generic key for Windows 10. Microsoft will have a footprint of the install to keep the install to a single machine, but currently, as I understand it, there is no separate key for a Windows 10 upgrade.

Also from what I have read, those moving free upgrade retail versions of 10 may be having to call MS to move their version to another PC, unless something changes of which I am not aware.
 
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