ReturningGuest search form is not working. Still combobxes, not textboxes. Did you provide the correct version of db? The values of comboboxes are the CustomerID but you have search criteria set up to use text values LastName, FirstName, MobilePhone. Either use the CustomerID field in search criteria or remove it from the combobox RowSource. Also, eliminate the combobox embedded macros.
Criteria with LIKE and wildcard would be:
[FirstName] Like [Forms]![ReturningGuest]![FirstName] & "*" And [LastName] Like [Forms]![ReturningGuest]![LastName] & "*" And [MobilePhone] Like [Forms]![ReturningGuest]![MobilePhone] & "*"
I changed the SearchByAll macro to this criteria and it runs without error but doesn't open form to the record. I really, really, don't like macros. This would be so simple with VBA or even the parameterized query demonstrated by the DataPig tutorial. Set the query as form RecordSource and use macro to open form but don't use the macro WHERE.
WAIT: finally got the macro WHERE to work, need quote marks:
"[FirstName] Like " & [Forms]![ReturningGuest]![FirstName] & "* And [LastName] Like " & [Forms]![ReturningGuest]![LastName] & "* And [MobilePhone] Like " & [Forms]![ReturningGuest]![MobilePhone] & "*"
However, you will find the results unsatisfactory when entering both name parts and they aren't a valid combination in the data. I would use a single combobox for name that concatenates the name parts:
SELECT LastName & ", " & FirstName AS CustName FROM GuestT;
Then use a query as the RegistrationF RecordSource and calculate CustName field in that query to concatenate the name parts.
The RealtorInformation subform on RegistrationF doesn't make sense - linking on HowDidYouHearAboutUs and RealtorCoID.