What you will achieve

Resolve Microsoft Office activation errors (unlicensed product, 0x4004f00c, subscription not found) using built-in repair and sign-in tools.

1) Confirm licence type

Open any Office app → File → Account.
Check whether it shows Microsoft 365 subscription, perpetual licence (Office 2021/2024), or Product Activation Required.
Work or school accounts need the org tenant to assign a licence — local fixes cannot override expired assignments.

2) Sign out and back in

File → Account → Sign out in Word or Excel.
Close all Office apps from Task Manager.
Reopen, sign in with the correct Microsoft work or personal account.

3) Run Office repair

Settings → Apps → Installed apps → find Microsoft 365 or Office → Modify (or three-dot menu → Modify).
Choose Quick Repair first; if activation still fails, run Online Repair (requires download, longer).

4) Reset activation state (last resort)

Admin Command Prompt — path varies by version:

cd "C:\Program Files\Microsoft Office\Office16"
cscript ospp.vbs /dstatus
cscript ospp.vbs /unpkey:<last 5 of key from dstatus>
cscript ospp.vbs /inpkey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

Only use /inpkey with your legitimate product key. For Microsoft 365, sign-in repair usually suffices.

5) Shared computer licensing

Microsoft 365 shared computer activation for lab PCs — enable via Office Deployment Tool or Intune.

6) Check multiple Office installs

Remove old Office 2016 MSI before installing Microsoft 365 Click-to-Run — mixed installs break licensing.
OffScrub scripts from Microsoft support remove stubborn remnants.

7) Licensing diag from Office

Run %programfiles%\Microsoft Office\Office16\OSPP.VBS /dstatus from elevated Command Prompt for KMS vs MAK vs M365 status.

8) Phone activation fallback

Perpetual Office with key but no internet: run setup.exe /phone after repair fails.
Microsoft automated phone system provides confirmation ID for offline activation — legitimate keys only.

Verification checklist

File → Account shows Product Activated. Close all Office apps, reopen — activation should persist. Document tenant vs retail licence type for future support.

Reboot once after changes that affect services, drivers, or firmware.
Confirm the original problem is resolved under normal daily use, not only immediately after the fix.
Note date, Windows version (Settings → System → About), and what changed in your personal runbook for next time.

Quick reference paths

File → Account in Word
Apps & features → Office → Modify
ospp.vbs /dstatus
Admin tools: press Win + X for Terminal (Admin), Device Manager, and Computer Management.