Steam installs updates to the wrong folder

If you moved your Steam folder then you need to delete the clientregistry.blob file because it stores the old Steam install path in it and can cause this problem.

This can also happen if you have multiple Steam installs to different locations.

You have to log out of Steam first, then delete that file.

When you start Steam back up it will re-create the blob file and imprint it with your new install location.