Are you thinking about switching your computer to Windows 10? It’s certainly an attractive proposition: Windows 10 has been offered as a free upgrade to most Windows PCs and laptops. But as with most things in technology, it doesn’t always go as planned. Before you upgrade your system to Windows 10, you should backup all your important data — and look out for these common issues.

Windows 10 Is Not Activated (Or the License Is Incorrect)

There are many ways that Windows computers can be licensed. Some individuals purchase copies of Windows on their own, but it’s more common for people to get computers that have been “mass licensed” by their vendors, such as Dell, or HP. When these licensed are used, they can occasionally be registered as incorrect or not eligible for the upgrade. Often, this situation can be resolved by updating your computer and making sure you have a copy of the license with you. The license should have either come with your computer, or there should be a Microsoft Windows sticker somewhere on the case. If the upgrade doesn’t work even after updating Windows, you can call Microsoft directly with your license number.

Windows 10 Is Not Compatible With Your PC

During installation, you may encounter some inherent system incompatibilities. There are two types: hardware (noted by an error message “0xC1900200 – 0x20008” and “0xC1900202 – 0x20008”) and software (noted by an error message “0xC1900208 – 0x4000C”). Hardware issues generally mean that your computer does not have the minimum specified hardware to run Windows 10 — in this situation, the only option is to upgrade your system. For software-level incompatibilities, you may need to restore or repair Windows. If this doesn’t work, you’ll need a professional to help you figure out which application is triggering the problem.