My Documents Redirection Is Unavailable Or Missing

If the option to redirect the target folder for My Documents you may be able to modify the registry to fix it. If you are on a network with a policy enabled, your change may be overridden by a domain policy.

Use regedit an delete the following value:

DisablePersonalDirChange

from

HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies \ Explorer