How To Fix the ‘Product Activation Failed’ Error in Microsoft Office

The dreaded “Product Activation Failed” error in Microsoft Word and other Office apps (like Excel, PowerPoint, etc.) is a total pain. Basically, the software can’t verify its license—either because it lost connection to Microsoft’s servers, the product key is invalid, or the license expired. Sometimes it happens after a trial runs out, or if there’s a mismatch with the Microsoft account linked to the license. Firewalls or network issues can also block activation, which is kind of frustrating because Office then switches to a crippled mode, limiting editing and features until it’s sorted out.

If it’s happening on your end, there are a few ways to get it back up and running. Some are quick, some a bit more involved, but all are worth trying if you want to avoid buying a new license or re-installing everything from scratch.

How to Fix “Product Activation Failed” in Office

Method 1: Running the OSPPREARM.exe as Administrator (Sometimes Needs Repetition)

This little tool, called OSPPREARM.exe, is basically a reset button for Office’s activation clock. It resets the license tokens and can extend the trial period a bit. On some setups, just running it 3–5 times might do the trick, especially if Office is in some weird limbo state. Kind of weird, but it works sometimes—especially with Office 2016 or Office 2019.

Find where Office is installed. Usually, for Office 2016, the folder is: C:\Program Files\Microsoft Office\Office16. For Office 365 or newer versions, it might be in C:\Program Files\Microsoft Office\root\Office16 or C:\Program Files (x86)\Microsoft Office\Office16. If you’re not sure, just search on your PC for OSPPREARM. EXE.
Right-click OSPPREARM. EXE and choose Run as Administrator. Do this 3–5 times, because sometimes it’s like hitting a reset button that needs a few presses to stick.
After that, open Word and see if the activation error disappeared. On some machines this fails the first time, then works after a reboot or a second try. So don’t give up if it’s not perfect the first shot.

Method 2: Using Command Prompt for a More Controlled Fix

If just clicking and running the tool isn’t enough, try this—especially if your Office installation is acting stubborn. Opening Command Prompt as Admin gives you a bit more control. This approach helps bypass a lot of common blockers like antivirus or background services.

Press Win + X and select Windows Terminal (Admin) or Command Prompt (Admin).
Type cd \ and press Enter. This takes you to the root directory.
Navigate to your Office folder. For most Office 2016/2019 installs, it’s: cd "C:\Program Files\Microsoft Office\Office16", or if you’re on a 64-bit system with 32-bit Office, it might be C:\Program Files (x86)\Microsoft Office\Office16.
Check your current license status with: cscript ospp.vbs /dstatus. It’ll tell you if Office thinks it’s activated or not.
To reset the license status, run: ospprearm.exe. Sometimes you might need to do this a couple of times—kind of annoying but worth it.
Once done, restart Office or your PC, then open Word to see if the activation issue is fixed. Usually, this process kicks Office out of its limbo and makes it think it’s legit again.

Method 3: Get a Genuine License (The Real Fix)

This one’s straightforward but crucial. The rearm tricks only work a handful of times—like five times max—so if it’s still broken or your trial expired, it’s time to buy a proper license. Whether you go for a subscription (Microsoft 365) or a one-time purchase of Office, make sure it’s genuine. Sign in with the Microsoft account associated with your purchase and ensure your internet connection is solid. Firewall or antivirus settings sometimes block the activation servers, so double-check those too.

If it still refuses to activate despite all this, contact Microsoft Support — they can often help verify your license or troubleshoot why it’s not working even with valid keys. Sometimes, direct support is the only way out when all else fails.

Most of the time, these tricks will get Office back in shape. Just remember that rearming is limited, so if the problem keeps showing up, a proper activation with a legit key is the way to go.

Summary

Trying OSPPREARM.exe a few times can reset activation timers temporarily.
Command Prompt method gives more control and might fix stubborn issues.
Buying a licensed copy is the permanent fix — don’t rely solely on rearm tricks.
Always check network and firewall settings if activation fails.

Wrap-up

This stuff can be a bit random—Windows and Office don’t always behave the same on every machine. But with these methods, there’s a decent shot at fixing the activation error without needing a full reinstallation. If nothing else works, it might be time to consider buying or reinstalling Office. Fingers crossed this helps some poor soul out there—worked for a few setups on my end, so hopefully, it does for you too.