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Sorry for the wait. My name is Michael. I will be helping you with your question today.
This may be from an update to your operating system. You are correct about this being an older version. Have you considered upgrading to a more recent version and then trying to re-link?
Also, were the original files moved outside of FCP, or were they on an external storage location? This can lead to the problem you describe.
You can request a phone call from your side. If you do that, you should receive a call back rather quickly.