Error 0xC004C003 encountered.
Error 0xC004C003 encountered.
Hello, I changed to Windows 10 Pro 64-bit from ISO, but now it won’t start and shows the 0xC004C003 error.
Your most recent serial output is "PKCKT WTF IS THIS?" and it seems your Windows version is Pro.
It doesn't matter which key you use. Microsoft stores the hardware ID in its records (your PC transmits it during activation). If that ID matches an active 7, 8.1 or paid Windows 10 key, the installation will activate. Otherwise, you'll encounter the error. I made a similar mistake once. I upgraded on one virtual machine and then attempted to apply the same key on another VM—it failed. To fix it, I installed Windows 8.1 on the target VM, performed the upgrade, and activation succeeded afterward. A solid system for Microsoft, but problematic for those who frequently switch hardware or rely heavily on VMs.
Now you're wondering about the process. Yes, it doesn't depend on the key you use. Even if you purchase an original Windows 10 key, it might not work properly. Make sure to verify compatibility and follow the correct steps.
New keys might not be the same as upgrades. I haven’t used them before since I don’t intend to pay for Win10. I think Microsoft will recognize the key during installation and link it to a specific hardware ID, which should work properly. If it fails, it could mean the key is already tied to another device or the servers are busy. You could try activating it via phone—though they didn’t make that easy.
1) Launch the command prompt as an administrator (my habit).
2) Enter "slui 4" without quotes.
3) Choose your country.
4) Dial the toll-free number if available (hide caller ID on mobile).
5) Follow the steps, which should be clear now.