How to download, install and activate Windows 10 Enterprise LTSC 2021
Windows 10 Enterprise LTSC 2021 is not on the consumer download page, so the ISO comes from your order email or the Microsoft Evaluation Center. Install it, then open Settings, Update and Security, Activation and enter the key. An Evaluation build needs converting first, and the LTSC image ships without the Microsoft Store and Edge.
| Official download | Link in your order email, or the Microsoft Evaluation Center |
|---|---|
| Installer type | ISO, written to an 8 GB USB stick |
| Time needed | 15 minutes for a key, 60 to 90 for a clean install |
| Activation | Settings > Update and Security > Activation, or slmgr |
| Supported until | January 2027, unlike the rest of Windows 10 |
| Free help | Email every day, phone Mon–Fri 9am–6pm ET |
Before you start
The dates matter here, so take them first. Microsoft ended support for ordinary Windows 10 on October 14, 2025, and there are no more security updates for it outside the paid Extended Security Updates program. LTSC 2021 is the exception: it stays supported into January 2027, which is why people pick it for machines that must not change, such as tills, kiosks and production line PCs.
- Your key and download link are in the order email. Both arrive in minutes, and sit in your account here.
- LTSC media is not on the Microsoft consumer page. That page offers Home and Pro only. Use the order-email link or the Evaluation Center.
- Evaluation builds need converting. An Evaluation install refuses retail keys with 0xC004F069. Email us for the conversion steps.
- The image has no Store and no Edge. Deliberate on LTSC. Step 2 covers what to do about it.
| Requirement | Minimum |
|---|---|
| Processor | 1 GHz or faster |
| Memory | 1 GB for 32-bit, 2 GB for 64-bit |
| Free storage | 16 GB for 32-bit, 20 GB for 64-bit |
| Graphics | DirectX 9 with a WDDM 1.0 driver |
| Display | 800 x 600 or higher |
| Other | Internet access and an 8 GB USB stick |
Download the Windows 10 Enterprise LTSC 2021 ISO
The long-term servicing build is not a consumer product, so there is no Media Creation Tool and nothing to pick on the ordinary Windows 10 download page. Use the link in your order email first. The Evaluation Center is the fallback, and it gives a build that has to be converted.
- Open the download link in your order email. It points at the correct LTSC 2021 ISO.
- Or register at the Evaluation Center. Microsoft asks for a few details, then serves the ISO.
- Check it says LTSC 2021. Not LTSB, and not the yearly Enterprise build.
- Write the ISO to a USB stick. Any standard imaging tool will do. The stick needs 8 GB.
- Note which build you have. Retail or Evaluation. It decides whether Step 3 works.
An Evaluation LTSC ISO is a full install with a time limit, and will not take your key until converted. Email contact@officegsm.com for the conversion steps.
Install LTSC 2021 and put back what is missing
The install runs like any other Windows 10 install. What surprises people is the desktop afterwards: LTSC leaves out the Microsoft Store, Edge, Cortana and the bundled apps on purpose, because a machine that never changes cannot have apps updating underneath it.
- Boot from the USB stick. Restart and tap the boot menu key, usually F12 or Esc.
- Pick language and keyboard, then Install now. Choose I do not have a product key.
- Confirm the edition reads Enterprise LTSC. If it offers Home or Pro, the ISO is wrong.
- Choose Upgrade or Custom. Custom wipes the partition you select.
- Wait out the restarts. Two or three reboots, then region and an account.
- Install a browser. No Edge in the image. Get it from microsoft.com, or install whichever browser your site uses.
There is no Microsoft Store on LTSC, and Microsoft does not support adding it. Install applications from their own installers, which is what a locked-down machine wants anyway.
Activate Windows 10 Enterprise LTSC 2021
Two ways in. Settings suits a single machine, the command line is quicker across several. Get the PC online first, or activate by telephone on an isolated machine.
- Open Settings with the Windows key and I. Then Update and Security, then Activation.
- Check the edition line reads Enterprise LTSC. And that it does not say Evaluation.
- Click Change product key. Paste the 25-character key from the order email.
- Click Next, then Activate. Allow a minute for the servers to answer.
- Or use the command line. Open Command Prompt as administrator and run slmgr /ipk followed by your key, then slmgr /ato.
- Read the result. It should say Windows is activated.
LTSC machines are often kept off the network, which is what telephone activation exists for. Our phone activation and Confirmation ID guide covers slui 4, and we will get the Confirmation ID for you.
Check that it worked
Two minutes of checking now saves a support call later.
- The edition line says Enterprise LTSC. With no Evaluation after it.
- Activation reads activated. Press Windows and R, run slmgr /xpr for a second opinion.
- The desktop watermark is gone. Both the Activate Windows text and any expiry notice.
- Windows Update still offers security updates. LTSC 2021 keeps receiving them into January 2027.
Common errors and how to fix them
These cover almost every LTSC 2021 ticket. If none helps, send us the code and your order number.
0xC004F069: this edition cannot be activated
The install is an Evaluation build, and evaluation editions refuse retail keys by design. Nothing typed into Settings will change that. The build has to be converted to the full edition first, and the key then goes in normally. Email contact@officegsm.com with the build number from Settings, System, About, and we will send the conversion steps that match your image.
0xC004F050: the product key is not valid
The installed edition does not match the key. LTSC 2021 counts as its own edition, so this key will not activate ordinary Windows 10 Enterprise or an older LTSB image, and their keys will not activate this one. Check the edition line in Settings, Update and Security, Activation, and if it is not LTSC, rebuild the USB stick from the ISO in your order email.
0xC004C003: the server says the key is in use
The key has already been activated elsewhere, or it has been blocked. Nothing on the PC fixes this, and reinstalling will not help. Check that you copied the key exactly, with no character missing at the end, then email contact@officegsm.com with your order number. We look it up and send a replacement, and if we cannot get you activated the 180-day guarantee means your money back.
0xC004F074: Windows cannot reach the activation servers
A connection problem rather than a key problem. Confirm the machine is online, then check the date, time and time zone, since a clock that is days out breaks the secure handshake. Leftover KMS settings from a company network do it too. On an isolated machine this is expected, and telephone activation is the answer: run slui 4 and follow our Confirmation ID guide.
Windows 10 LTSC 2021 download questions
What people ask us most about the Windows 10 Enterprise LTSC 2021 download.
How long is Windows 10 Enterprise LTSC 2021 supported?
Into January 2027, which is the reason most people buy it. Ordinary Windows 10 stopped receiving security updates on October 14, 2025, but the long-term servicing channel runs on its own longer clock and LTSC 2021 keeps getting security fixes until that date. What it does not get is new features, by design: the build stays as it shipped, so nothing changes under a machine that has been validated and left alone. When the date passes, the same rules apply as any other end of support.
Why is there no Microsoft Store or Edge?
Because LTSC is built for machines that must not change. The Store, Edge, Cortana and the bundled Store apps all update on their own schedules, so Microsoft leaves them out of the image entirely. You can install Microsoft Edge from microsoft.com like any other application, and any other browser installs normally too. The Store itself is not supported on LTSC and should not be added, so plan on installing software from its own installer, which is what most locked-down machines do anyway.
Will my LTSC 2021 key activate ordinary Windows 10 Enterprise or Windows 11?
No. LTSC 2021 is a separate edition, so this key activates LTSC 2021 and nothing else, and an ordinary Enterprise key will not activate an LTSC install either. Mixing them gives 0xC004F050. The general Windows 10 rule, that a key activates the matching Windows 11 edition on supported hardware, does not stretch to the servicing channels. If you want to move a machine to Windows 11, our Windows 11 Pro guide and the Windows 11 keys are the place to start.
Should I choose LTSC 2021 or ordinary Windows 10 Enterprise?
Choose LTSC when the machine has one job and must keep doing it the same way: a till, a kiosk, an instrument controller, a production line PC. You get security updates into January 2027 and no feature changes at all. Choose ordinary Windows 10 Enterprise for a desktop that people actually work at, because the missing Store and Edge and the frozen feature set get in the way there. If you are unsure, tell us what the machine does and we will say which one fits.
Need a genuine LTSC 2021 key?
$10.95 one time, emailed in minutes, covered by our 180-day guarantee. Not sure LTSC is the right build? Compare Windows 10 Enterprise and all Windows 10 keys.