How to install Microsoft Office 2021 Professional Plus on 5 PCs
The 5 PC pack is the same Office LTSC Professional Plus 2021 as the single licence, with enough activations for five computers. Download the installer from the link in your OfficeGSM order email, install it on each PC, then activate in Word under File, Account, Change Product Key. Budget 15 to 30 minutes per machine, and skip setup.office.com.
| Official download | Link in your order email, or the Office Deployment Tool |
|---|---|
| Installer type | 64-bit Click-to-Run, perpetual volume channel |
| Time needed | 15 to 30 minutes per computer |
| Activation | 25-character key in Word, repeated on each PC |
| Works on | Five Windows 10 or Windows 11 computers |
| Free help | Email every day, phone Mon–Fri 9am–6pm ET |
Before you start
Read your order email first: it states how many activations your key covers, and lists more than one key if that is what we sent. Work through one computer at a time and note which key went on which machine.
- Read the order email carefully, for the download link, the key or keys, and the activation count.
- Keep a list of which computer got which key, with the date.
- Uninstall every other Office on each PC, in Settings, Apps, Installed apps, including Microsoft 365 and preinstalled trials.
- Do not sign in with a Microsoft account, which can replace your license with a Microsoft 365 trial.
- Do one machine at a time, and check it says Product Activated before starting the next.
| Requirement | Minimum |
|---|---|
| Operating system | Windows 10 or Windows 11 on every computer |
| Not supported | Windows 8.1 and older, macOS, Chromebook, Linux |
| Apps included | Word, Excel, PowerPoint, Outlook, OneNote, Access, Publisher |
| Licensing | Five activations, perpetual, no subscription |
| Supported until | October 13, 2026 |
| Full details | Microsoft’s system requirements page |
Download Office LTSC Professional Plus 2021 once
One download serves all five computers. The link in your order email points at Microsoft’s Click-to-Run installer for the perpetual volume build, the build your key matches. Nothing is redeemed on a web page first: setup.office.com serves retail cards and answers “Service unavailable” for a volume key.
- Open your OfficeGSM order email and note the download link, the key or keys, and the activation count.
- Download the installer once. The 64-bit build is standard, and one copy can be reused on every PC.
- Copy it to a USB stick or a shared folder, which saves downloading it five times.
IT teams can pull the same files from Microsoft with the Office Deployment Tool. Save the file below as configuration.xml beside setup.exe, then run both commands from an administrator Command Prompt.
<Configuration>
<Add OfficeClientEdition="64" Channel="PerpetualVL2021">
<Product ID="ProPlus2021Volume">
<Language ID="en-us" />
</Product>
</Add>
<Display Level="Full" AcceptEULA="TRUE" />
</Configuration>setup.exe /download configuration.xml
setup.exe /configure configuration.xmlInstall on each of the five computers
The install is the same on every machine, and it never asks for a product key. That is normal for this edition, because the key goes in later, inside Word.
- Uninstall any existing Office on that PC first, then restart it.
- Run the installer and approve the prompt from Windows.
- Get past SmartScreen. On “Windows protected your PC”, click More info, then Run anyway. If nothing happens at all, turn Smart App Control off in Windows Security.
- Wait for the message saying you are all set. All seven apps, including Access and Publisher, are then in the Start menu.
- Move on only once that PC is activated, using the step below.
If a sign-in box appears, close it. A Microsoft account is not needed here, and signing in is the quickest way to end up with a Microsoft 365 trial instead.
Activate Office 2021 on each PC with your product key
Activation is done once per computer, in any app, and covers the whole suite on that machine. Use the key from your order email, then tick it off your list.
- Open Word on the computer you have just set up. Close the start screen.
- Click File, then Account, near the bottom of the left-hand column.
- Click Change Product Key, which sometimes reads Activate Product on a fresh install.
- Paste the 25-character key rather than typing it, which avoids mix-ups between 0 and O.
- Let activation finish, then reopen Word and check the panel says Product Activated.
- Write down which key went on this PC, then repeat the whole process on the next one.
If you see 0xC004C020, or a message about a Multiple Activation Key reaching its limit, the activations on that key are spent. It usually means one PC was rebuilt or the key went on a sixth machine. Finish by telephone with our phone activation and Confirmation ID guide, or email us and we will check the count.
Check that it worked
On every computer, open Word, click File and then Account, and compare the panel with the lines below.
- The product name reads Office LTSC Professional Plus 2021. Anything else means an older Office is in charge on that PC.
- The status says Product Activated, with no countdown or coloured banner.
- Your list is complete, with one key noted against each computer.
- Access and Publisher open, because all seven apps share the activation.
Common errors and how to fix them
The messages our team sees most often on multi-PC packs, cause first and fix after. If yours is not here, send us a screenshot.
0xC004C020 before all five PCs are done
The online activations on that key are spent, usually because a machine was rebuilt and activated twice, or the key reached a sixth computer. Finish this PC by telephone: in Word, File, Account, Change Product Key, click Back when the error appears and choose to activate by telephone, then use the Installation ID to get a Confirmation ID. Email us your order number too and we will check the activation count.
I cannot tell which key belongs to which computer
Your order email is the record of what we sent, so open it and count the keys against the machines you have set up. Where a key is already in use, Word on that PC shows its last five characters under File, Account, which is usually enough to match them up. Send us your order number if the picture is still unclear and we will tell you what was delivered.
Error 30015-25 or 30038-25 on one of the computers
The installer has stopped because another Office is already on that machine, and the two cannot share a computer. In Settings, Apps, Installed apps, uninstall every Office and Microsoft 365 entry, including the preinstalled trial, then restart and run the installer again. If the error returns, files are still on the disk, and Microsoft’s Office uninstall support tool clears them. Restart once more afterwards.
0xC004C003 or “the specified product key is blocked”
A blocked key is one Microsoft has pulled on their own servers, so nothing on your PC will fix it. Email your order number and a screenshot to contact@officegsm.com. We check the key with our supplier and send a replacement free of charge, usually the same day, and it goes in the same way under File, Account, Change Product Key. The other computers in your pack are not affected.
Office 2021 Professional Plus 5 PC questions
Answered by the team that handles our tickets every day.
Do the five computers have to be in the same house or office?
No. The activations are yours to place wherever you need them, so a home desktop, a laptop, a machine at a second address and two office PCs are all fine. Each computer needs its own installation and its own activation, and each one has to be online at the moment you enter the key. What matters is the count rather than the location. Keep a note of which key went on which machine, because that list is what makes a rebuild or a replacement PC straightforward later on.
Can I install Office 2021 on a sixth PC if one computer dies?
Retiring a machine does not automatically hand its activation back, so a sixth install will usually be refused with 0xC004C020. Telephone activation solves it in most cases, because the automated line issues a Confirmation ID once you confirm the software is on one computer. Our Confirmation ID guide walks through it. If the line refuses, email contact@officegsm.com with your order number and we will look at the key and sort out a replacement where that is warranted, inside the 180-day window.
Is the 5 PC pack the same software as the single licence?
Yes, exactly the same Office LTSC Professional Plus 2021, with Word, Excel, PowerPoint, Outlook, OneNote, Access and Publisher, and the same installer. The only difference is how many computers the licence covers. If you only need one machine, the single PC guide covers the same steps for one machine. Microsoft supports this release with security updates until October 13, 2026, after which the apps keep working but stop receiving fixes, so plan a move to Office 2024 at some point if the machines are online.
Can I redeem the key at setup.office.com for the 5 PC pack?
No. That page exists for retail Microsoft 365 subscriptions and retail Office cards sold in shops. This is the volume-licensed perpetual edition, so setup.office.com returns “Service unavailable” or says the key is invalid, and neither message tells you anything about your key. Install Office first from the link in your order email, then enter the key on each computer in Word under File, Account, Change Product Key. That is the only place a key like this is accepted, and the same is true on all five machines.
Need Office 2021 Professional Plus for five computers?
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