Can't activate Windows, error code 0x803FABC3

Question

Can't activate Windows, error code 0x803FABC3

Kory Albright 0

When I try to activate Windows, it fails.

I tried clicking "I changed hardware on this device recently" and that didn't help either.

I did change hardware recently, and i reinstalled windows because my old motherboard died and I upgraded as well. I activated windows In a VM and that worked, but it doesn't work for my host PC. Nothing i have tried works. Before this, i tried to activate windows with the placeholder key, which didn't work. I get the error code

0x803FABC3

.

The old specs are as follows if needed:
Ryzen 5 3600

64GB DDR4-3200MHz RAM

RTX 4060

GIGABYTE B550 GAMING X V2

Here are the new specs if needed as well:

Ryzen 5 9600x

RTX 4060

16GB DDR5-6000 MHz RAM

MSI PRO-B850-S WIFI

Kory Albright 0 Reputation points

2026-01-17T17:40:06.79+00:00

I forgot to mention I ran the troubleshooter and that didn't help. I have also signed in with the correct Microsoft account, and the device is listed, but when I try anything it fails.

3 answers

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Kory Albright 0 Reputation points

2026-01-17T17:40:06.79+00:00

I forgot to mention I ran the troubleshooter and that didn't help. I have also signed in with the correct Microsoft account, and the device is listed, but when I try anything it fails.

Answer 1

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Answer 2

EmilyS726 205.4K Independent Advisor

Hello

Do you still have this license installed on the VM? If so, do this in the VM, Can you please type cmd in the search on the taskbar and hit enter to launch command prompt, then run the following command:

slmgr /dlv

Then share a screenshot please. Thanks!

Kory Albright 0 Reputation points

2026-01-18T00:08:24.74+00:00

Here is the VM's license info:
EmilyS726 205.4K Reputation points Independent Advisor

2026-01-18T03:59:27.9866667+00:00

On the host computer, do you also have Windows Home edition installed?

When was the last time you used this license to activate any Windows? For example, less than 3 months ago, or more than 3 months ago?
Kory Albright 0 Reputation points

2026-01-18T08:44:49.57+00:00

I have windows 11 home edition installed. I think i used it to activate windows more than three months ago, if we're not counting the vm. if we're counting the vm, i installed windows on it to see if the key still worked. it doesn't work on my host computer, which is the one running the virtual machine.
Kory Albright 0 Reputation points

2026-01-18T08:46:37.6+00:00

whats weird is that it activated in the vm with no issue, but my host computer is the one having trouble with the activation.
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-18T14:46:46.71+00:00

You have used the licence on the VM are you trying to transfer that licence to the host?

In your screenshot it shows the last 5 characters of a generic key so it appears to be a digital licence or was a Windows 7 or 8 licence.
EmilyS726 205.4K Reputation points Independent Advisor

2026-01-18T16:10:18.1866667+00:00

So, in another word, your VM was just activated?

Just want to make sure this is how you ran the troubleshooter, right?

go to Settings > System > Activation, run the troubleshooter, choose the hardware change option. When it asks you where it is installed on right now, you should choose the old device name (vm). Then click on Activate button. And on the next screen when it asks you where to transfer it to, choose your new device name (host).

If so, it can be due to the VM was just recently activated. This is an unspoken rule, if you activate the same license on different device/install in a short period. this can be anti-abuse/activation system behavior.

If you have purchase proof, you can also chat with support, and ask for them to manually activate for you.

To get help, open the "Get Help" app on your computer (just search for it in the Start menu). or go to https://support.microsoft.com/contactus, Type "Billing" and press Enter. On the next screen, click "Contact support" at the bottom of the page, then choose "Windows" > "Manage my subscription". You’ll then see the option to chat with a Microsoft support agent who has access to your account to help review the issue.
Natalia Korzanova 0 Reputation points

2026-01-27T17:22:32.3+00:00

Hello!

I am currently having an error code 0x803FABC3 with windows 11 on VM after Mac OS update.

what is the next step would you suggest after screenshotting the information slmgr/dlv command reveals?
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-27T19:13:58.07+00:00

@Natalia Korzanova it depends on the info in the screenshot.

Post it here so we can have a look.

Where did you get the licence for windows.?
Natalia Korzanova 0 Reputation points

2026-01-27T20:12:58.55+00:00

I got the license from online Microsoft store in November

Now it shows error 0x803FABDD

Here is a screenshot
Natalia Korzanova 0 Reputation points

2026-01-27T20:13:28.5133333+00:00

IMG_1108.png
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-27T22:22:48.94+00:00

@Natalia Korzanova The licence looks to be okay. It is for Home edition is that correct.

Was windows activated and now it is not?

You should be able to see the whole product key if you get ShowKeyPlus from the Store and look at the Installed key. The last 5 characters should match what is shown on your screenshot.

If for some reason windows is no longer activated then make a note of the 25 character key ending in QRR7H and enter the whole key in Settings at Change product key. The easiest way to find it is to search settings for "Change product key".

See if windows then activates.
Natalia Korzanova 0 Reputation points

2026-01-27T22:46:18.41+00:00

Yes, it is Home addition and it was activated.

I followed all the steps you have suggested. It says “unable to activate windows” error 0x803fa067
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-28T15:05:39.26+00:00

@Natalia Korzanova

I've not come across this error code specifically but it does relate to activation possibly during a Home to Pro upgrade. In ShowKeyPlus can you select Check edition and enter the product key that ends in QRR7H just to confirm what the product key is for.

It should show Windows 10/11 Home Retail.

There seems to be an option to try entering the product key while offline to see if the key is accepted. Restart then reconnect to the internet again.

If the ShowKeyPlus app confirms the correct licence (and I can see you have Windows Core, which is Home edition) then your only option is going to be the Get Help app in windows to contact Microsoft support directly.

Type in chat with an agent then select Contact Support.

There may be an outside chance there is something wrong with windows activation services and you could try a repair install using the built-in option in Settings > System > Recovery > Fix problems using windows update and select Reinstall now.
Natalia Korzanova 0 Reputation points

2026-01-28T15:16:50.2633333+00:00

Edition is Win 10 RTM Core Retail

I’ll try to reactivate offline

Thank you so much for your help and such clear instructions!

I had unsuccessful interaction with an agent yesterday. As soon as they found out I was using virtual machine, they told me to go to VMware technical support. I still fail to understand how anyone else but Microsoft can help with activation.
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-28T15:25:40.0166667+00:00

@Natalia Korzanova

Whether using a VM or hardware, activation is the same. If the device has changed in anyway it may be worth trying the activation troubleshooter and select Changed hardware even if you haven't. (so far as you are concerned)

I fail to see why they make a distinction between the two.
Natalia Korzanova 0 Reputation points

2026-01-28T15:59:16.81+00:00

Could not find the option to activate it offline.

My initial move was to use the “I changed my hardware” option. I assumed that Mac OS upgrade makes windows read VM as a new device. The message I get is “We can’t activate your copy of Windows as the digital license for this device has already been used to reactivate Windows.”
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-28T16:08:12.0466667+00:00

@Natalia Korzanova

I would expect to take the system offline (disconnect from the internet) then input the product key at Change product key and follow any prompts. I don't think there is a specific option to select. (like activate offline)

The only other thing you can do is the Reinstall now option. Otherwise it's down to Microsoft Support.

All we can offer from this forum relates to the available auto activate options. Only Microsoft support can do more. Perhaps when you contact them again don't mention a VM.
Natalia Korzanova 0 Reputation points

2026-01-29T14:59:36.1266667+00:00

It doesn’t let me to do it offline.

It is a good idea not to mention VM with Microsoft Support. I’ll do this first.

Thank you!
Neil D 31,930 Reputation points Volunteer Moderator

2026-01-29T15:12:57.1+00:00

There's another user with a digital licence in a thread I've been looking at. An independent advisor posted the following for activation issues. (don't know if it will help you) Open the "Get Help" app on your computer (just search for it in the Start menu). or go to https://support.microsoft.com/contactus, Type "Billing" and press Enter. On the next screen, click "Contact support" at the bottom of the page, then choose "Windows" > "Manage my subscription". You’ll then see the option to chat with a Microsoft support agent who has access to your account to help review the issue.
Natalia Korzanova 0 Reputation points

2026-02-06T13:53:13.92+00:00

Oh boy, after having Windows reinstalled 2 times with 4 different agents who tried it seems like everything, I still have the same problem. My next step is to reach out to VMware support to see if anything can be done on a level of a VM.

Thank you for your support!

Answer 3

The error code 0x803FABC3 typically indicates that there is an issue with the activation of Windows due to hardware changes. Since you have recently changed your motherboard and other components, this can affect the activation status of your Windows license. Here are some steps you can take to resolve the issue:

Use the Activation Troubleshooter: Since you mentioned trying to activate after changing hardware, ensure you are using the activation troubleshooter effectively. Go to Settings > Update & Security > Activation and select Troubleshoot. This can help in reactivating Windows by recognizing the hardware changes.
Sign in with the Correct Microsoft Account: Make sure you are signed in with the Microsoft account that was used to purchase or activate Windows initially. This is crucial for digital license verification.
Check Device List: Verify that your device is listed under your Microsoft account. If it’s not, you may need to unlink your old device and try to link the new one.
Use a Product Key: If you have a valid product key, you can try entering it manually. Go to Settings > Update & Security > Activation and select Change product key.
Contact Microsoft Support: If the above steps do not work, contacting Microsoft Support may be necessary. They can assist you in reactivating your license, especially if it involves hardware changes.
Consider Reinstalling Windows: If you have reinstalled Windows, ensure that you are using the same version (Home or Pro) that matches your license.

If these steps do not resolve the issue, it may be beneficial to look into the specific error messages provided by the troubleshooter for further insights.

References:

Kory Albright 0 Reputation points

2026-01-17T17:42:10.3566667+00:00

Windows was activated before the hardware change, and I reinstalled Windows after setting up my new parts.

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Can't activate Windows, error code 0x803FABC3

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