Unable to Unlink previous Nest account - Cannot migrate from Nest to Google

[WyomingDarren]

After 15 years with Nest, I have three homes with Nest thermostats, and cameras with saved clips. I have finally given in and will migrate to Google Home. Unfortunately when I try the migration process I keep getting the error "Your Google account is associated with another Nest account".

I have no recollection of ever having another Nest account, and am unable to "unLink" such account (each time I do so in Google Account Settings, Privacy and Security, Third Party Integrations", the association re-appears.  

How can I actually migrate in this scenario?
Can Google assist me in determining and/or deleted said current association?

Thank you in advance for any ideas....

[David_K]

@WyomingDarren 

Unfortunately, it's not possible to unlink a Google account and Nest account that are already linked to each other. You essentially have 2 options.

Use the Google Account that's linked to another Nest account:

1. Sign in to the Nest app with your Nest account.
2. Disconnect all your devices.
3. Sign out of the Nest app.
4. Select Sign in with Google > sign in with the linked Google Account.
5. Reconnect your devices.

Use a new Google Account:

1. Create a new Google Account.
2. Migrate your Nest account to the new Google Account.