Install Microsoft 365 on Windows or Mac

Microsoft still sells subscriptions that install Word, Excel, PowerPoint, Outlook, and the rest of the desktop suite — people just call them different names. Office 365 was the old brand; Microsoft 365 is what you see on packaging and account pages now. The install path is the same idea: sign in with the Microsoft account that owns the license, download the installer, run it, then open an app and sign in again to activate.

Below is the current flow for Windows and Mac, plus product-key redemption, work vs personal accounts, and the usual “already installed / wrong account / activation failed” fixes.

Install Microsoft 365 (Office)

Office 365 vs Microsoft 365 (same install, new name)

If your receipt, box, or IT email still says Office 365, you are not lost. Redeem and install under Microsoft 365 / Office apps. One-time perpetual products (Office Home 2024 and similar) also download from the same Microsoft account services page — the steps below still apply, minus the subscription renewal bits.

Redeem a product key (once per key)

New boxed or card keys need to be tied to an account once:

Go to microsoft365.com/setup (office.com/setup still redirects).
Sign in with the Microsoft account you want to own the license — or create one.
Enter the 25-character product key and follow the prompts.

After that, you do not re-enter the key on every PC. You install from the account that holds the subscription. Renewals should use the same account so you do not split licenses across two logins.

If you bought through a retailer and the key is still sealed, redeem it before you need Office on a flight — activation needs a network the first time. Families sharing a Microsoft 365 Family plan should each use their own Microsoft account under the organizer’s group, not one shared password for Word.

Install Microsoft 365 on Windows

Sign in at microsoft365.com/apps or account.microsoft.com/services with the account that owns Microsoft 365.
Select Install apps (or Install) for Microsoft 365 / Office apps. Prefer the 64-bit installer unless you know you need 32-bit for a legacy add-in.
Open the downloaded OfficeSetup.exe (or similar) and allow it to make changes when Windows asks.
Wait for the “You’re all set” screen, then close the installer.

Apps appear in the Start menu. If nothing shows up, search Start for Word or Excel and pin what you use.

On ARM-based Windows PCs (Snapdragon laptops), use the installer Microsoft offers for that device from the same account page. If an old 32-bit-only add-in is mission-critical, test it before you remove the last working Office build.

Install Microsoft 365 on Mac

On the Mac, sign in at the same Microsoft 365 apps or account services page.
Choose Install for Mac and download the .pkg installer.
Open Finder → Downloads, double-click the Microsoft Office installer package, then Continue → Agree → Install.
Enter your Mac login password when asked, wait for the install to finish, then Close.

Word, Excel, PowerPoint, Outlook, and the other apps land in Applications. The first launch may walk through a short welcome.

Mac App Store listings for Microsoft apps exist for some SKUs, but the classic path above — download the .pkg from your Microsoft account — is still the reliable way for full Microsoft 365 desktop suites. If IT manages your Mac with Company Portal, follow their install button instead of a personal download.

Open Word or Excel and sign in with the same Microsoft account (or work account) that owns the license. Activation is account-based for Microsoft 365 — if you signed into the wrong profile, Office acts like a trial or refuses to edit.

Personal Microsoft 365 plans typically allow install on multiple devices with a limit on how many can be signed in at once (commonly up to five). Sign out on an old PC when you move.

Offline editing still works after activation for a stretch, but Microsoft 365 wants periodic sign-in checks. If you travel without reliable internet, open the apps and confirm activation while online before you leave.

Work or school account vs personal account

Personal (outlook.com, hotmail, live, gmail-linked Microsoft account): use account.microsoft.com/services and the consumer Install button.

Work or school: sign in at microsoft365.com with your org email. Your admin may push apps via Intune or block downloads. If Install is missing, ask IT — it is often a license or policy issue, not a broken link.

Reinstall, uninstall, and common errors

Reinstall: uninstall Microsoft 365 / Office from Settings → Apps (Windows) or move the Microsoft apps to Trash (Mac), restart, then install again from the account page.
Stuck installer / error codes: Microsoft’s Support and Recovery Assistant (Windows) can repair or fully remove leftover Office bits before a clean install.
“Product deactivated”: usually wrong account, expired subscription, or too many devices signed in — fix the account first, not the EXE.
Old Click-to-Run vs MSI: modern Microsoft 365 uses Click-to-Run. Mixing ancient volume MSI builds with Click-to-Run on one PC causes weird conflicts; uninstall the old stack first.

FAQs

Is Office 365 the same as Microsoft 365 for installing apps?

For getting Word and Excel on your computer, yes — sign in and install from the Microsoft account that holds the license. Microsoft 365 is the current brand; older emails may still say Office 365.

Do I need the product key every time I install?

No. Redeem a retail key once at microsoft365.com/setup. After that, install from the signed-in account page.

Can I install on both a Windows PC and a Mac?

Yes, within your plan’s device limits. Use the Windows or Mac installer from the same account.

Why does Word say I need to activate?

You are signed into a different account than the one that owns the subscription, the subscription expired, or the device limit was hit. Sign out of Office and sign in with the correct account.