How to Set Up Microsoft Office 365 on All 5 Devices — Complete UK Installation Guide (2025)
You have just bought an Office 365 Pro Plus lifetime licence that covers 5 devices. Brilliant decision — at £19.99 from Softkeys.uk, it is the best value Microsoft Office deal available to UK buyers in 2025. But now you need to actually install it on all your machines.
This guide walks you through the entire process, step by step, on both Windows and Mac. No jargon, no assumptions, no skipped steps. Whether you are setting up your first device or your fifth, follow along and you will have the full Office suite running in under 15 minutes per machine.
Before You Start — What You Need
Before installing on any device, make sure you have:
- Your product key — Softkeys.uk delivers this instantly via email after purchase
- A Microsoft account — If you do not have one, create a free account at account.microsoft.com
- Internet connection — You need broadband to download the installer (approximately 4GB)
- Sufficient storage — Office requires roughly 4GB of free disk space on each device
Important: Use the same Microsoft account for all 5 devices. Your licence is tied to the account, not the individual machines. This is what allows you to manage installations and transfer to new devices later.
Step 1 — Redeem Your Product Key
This step only needs to be done once, regardless of how many devices you plan to install on.
- Open your web browser and go to setup.office.com
- Sign in with your Microsoft account (or create one if needed)
- Enter your 25-character product key exactly as provided in your Softkeys.uk email
- Follow the on-screen prompts to link the key to your account
- You will see a confirmation message once the key is successfully redeemed
Once redeemed, your product key is permanently linked to your Microsoft account. You will not need to enter the key again on subsequent devices — just sign in with the same account.
Step 2 — Install on Your First Windows PC
With your key redeemed, installing Office on a Windows PC is straightforward:
- Go to account.microsoft.com/services and sign in
- Find your Office subscription/licence and click Install
- The installer file (OfficeSetup.exe) will download — run it
- The Click-to-Run installer will begin downloading and installing Office apps
- A progress bar will show the installation status — this typically takes 10-15 minutes on UK broadband
- Once complete, open any Office app (Word, Excel, etc.)
- Sign in with your Microsoft account when prompted
- Office will activate automatically — you should see "Account" > "Product Activated" in any Office app
That is it for your first device. Word, Excel, PowerPoint, Outlook, OneNote, Access, and Publisher are now installed and ready to use.
Step 3 — Install on Your Second (and Third, Fourth, Fifth) Windows PC
The process for additional Windows devices is identical:
- On the new device, open a browser and go to account.microsoft.com/services
- Sign in with the same Microsoft account you used to redeem the key
- Click Install again
- Run the installer and wait for it to complete
- Open an Office app and sign in — it will activate automatically
There is no need to enter the product key again. Your Microsoft account remembers that you have a valid licence, and each device simply checks in with Microsoft's servers to confirm.
Step 4 — Install on a Mac
If one or more of your 5 devices is a Mac, the process is slightly different:
- On your Mac, open Safari (or any browser) and go to account.microsoft.com/services
- Sign in with your Microsoft account
- Click Install — the Mac installer will download automatically
- Open the downloaded .pkg file
- Follow the macOS installation wizard — click Continue, agree to the licence terms, and click Install
- You may need to enter your Mac's administrator password
- Once installed, open any Office app (Word is usually the quickest to test)
- Sign in with your Microsoft account and Office will activate
The Mac version of Office includes Word, Excel, PowerPoint, Outlook, and OneNote. Note that Access and Publisher are Windows-only applications and are not available on macOS. This is a Microsoft limitation, not a licence restriction.
Step 5 — Verify All Devices Are Activated
After installing on all your devices, it is worth verifying that each one is properly activated:
- Open any Office app on each device
- Click File > Account (on Mac: click the app name > About)
- Look for "Product Activated" or "Subscription Product" — this confirms your licence is working
- If you see "Activation Required" or "Unlicensed Product," try signing out and back in
You can also check all your active installations at account.microsoft.com/devices. This page shows every device where Office is currently installed under your account.
Managing Your Devices — Adding and Removing Machines
Life happens. Laptops break, get replaced, or get handed down. Here is how to manage your 5 device slots over time:
To Remove a Device (Free Up a Slot)
- Go to account.microsoft.com/devices
- Find the device you want to remove
- Click Sign out or Remove device
- The slot is now free for a new installation
To Add a New Device
- Ensure you have a free slot (remove an old device if needed)
- On the new device, go to account.microsoft.com/services
- Sign in and click Install — follow the standard process
This flexibility is one of the major advantages of the Office 365 licence over individual Office 2024 keys, which are typically tied to specific hardware.
Troubleshooting Common UK Installation Issues
Most installations go smoothly, but here are the most common issues UK users encounter and how to fix them:
Problem: "This product key has already been used"
Cause: You are trying to redeem the key on a different Microsoft account than the one you originally used.
Fix: Sign in with the Microsoft account where you first redeemed the key. If you cannot remember which account, check the email you received from Softkeys.uk — it may reference the account used during setup.
Problem: Installation stalls or is extremely slow
Cause: Usually a slow or unstable internet connection.
Fix: Try connecting via Ethernet instead of Wi-Fi. If you are on a shared connection (common in UK households during evening hours), try installing during off-peak times. The download is approximately 4GB, so a 50 Mbps connection should complete it in about 10 minutes.
Problem: "We couldn't verify your licence" after installation
Cause: The device cannot reach Microsoft's activation servers.
Fix: Check your internet connection, disable any VPN temporarily, and try again. If using a corporate network, your employer's firewall may be blocking activation — try on your home network instead.
Problem: Office installed but some apps are missing
Cause: On Mac, Access and Publisher are not available (Windows only). On Windows, all apps should install — if some are missing, the installation may have been interrupted.
Fix: On Windows, go to account.microsoft.com/services and click Install again. The installer will repair or complete the installation without affecting your existing setup.
Optimising Office After Installation — Quick UK Tips
Once Office is installed on all your devices, take five minutes to optimise the setup:
Set Your Default Save Location
By default, Office may save to OneDrive. If you prefer local storage or a different cloud service, go to File > Options > Save and change the default save location. This applies per device, so set it on each machine.
Configure Outlook for Your Email
Outlook supports multiple email providers — Gmail, Yahoo, iCloud, and of course Microsoft accounts. Add your email accounts on each device so your mail is accessible everywhere.
Enable AutoSave
If you use OneDrive or SharePoint, enable AutoSave in Word, Excel, and PowerPoint. This saves your work in real-time and prevents data loss. Toggle it on via the switch in the top-left corner of any document.
Set Regional Preferences to UK
Office sometimes defaults to US English spelling and date formats. To fix this:
- Open any Office app
- Go to File > Options > Language
- Set English (United Kingdom) as your preferred editing language
- This ensures colour, licence, programme, and other UK spellings are used in spell check
Security Considerations for UK Users
When you install Office on 5 devices, you are sharing one Microsoft account across all of them. Keep these security practices in mind:
- Enable two-factor authentication on your Microsoft account — this is the single most important step to protect all 5 installations
- Use a strong, unique password for your Microsoft account — do not reuse it elsewhere
- Review your device list regularly at account.microsoft.com/devices — remove any devices you no longer own
- Be cautious on shared devices — if one of the 5 devices is a shared family computer, ensure other users cannot access your Microsoft account credentials
Why UK Buyers Choose Softkeys.uk for Office 365
Setting up Office across multiple devices requires a reliable, genuine product key. Softkeys.uk is a UK-registered business with:
- 8,174+ verified customer reviews with a 4.28-star rating
- Instant digital delivery — no waiting for post
- Lifetime warranty — if your key ever stops working, they replace it free
- UK-based customer support to help with any installation issues
The licence is legally sold under principles from the UsedSoft v Oracle ruling, with full UK consumer protection under the Consumer Rights Act 2015. Your purchase is legitimate, your software is genuine, and your rights as a UK consumer are fully protected.
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