How do I unlink an existing asset from multiple loan accounts?

Choose Tools menu > Accounts List. 

Click the Edit button next to the first loan account you want to work with.

From the Linked Asset Account drop-down list, select (none).

Quicken refreshes the window and displays (none) next to the attribute Linked Asset Account.

Repeat steps 1 through 4 for any other loan accounts linked to this asset.

From the Account List, select the house account associated with these loans. Click Edit.

In the Account Details window next to the Mortgage Account attribute, Quicken should display just the name of the remaining linked mortgage account or (none) if you unlinked all loan accounts. If after unlinking one or more loan accounts you still have more than one remaining linked loan account, then Quicken displays Multiple Loan Accounts.