The cloud is a useful place to store various files. But it’s probably not the safest place to store really important data, like the encryption key to your Windows PC. Unfortunately, Microsoft seems to be storing this online. So, what should you do about this? Head to the OneDrive Recovery Key site and log into your Microsoft account. If you find your key there, back it up somewhere like a flash drive that you will keep safe and then delete it from the site. Make sure it’s in a physically safe location that no one you don’t trust can get to.
Source: SlashGear