The following screen capture shows the the 'Access - W8RID' database tab for the ODBC definition I created to open your Access .mdb file, and after I restored the latest XML backup file you sent, it now contains all of your 1,754 contacts up to 2017-04-30 21:28:30:
However, the .mdb file you sent me previously only had 1,258 contacts up to 2015-05-29 12:25:15 as previously posted in your 'not_showing_all_contacts_in' topic.
So, I believe that you may have selected the wrong HRD Logbook database in the QSO Relay configuration settings, as it appears as though QSO Relay is fetching the 1,258 rows from a different Access database file.
The text on the tab of the open database in HRD Logbook - Access - W8RID', comes from the Title in Logbook Databases dialog in HRD:
As you can see in the following screen capture, the Logbook Database: drop down listbox In the QSO Relay configuration dialog lists of the database titles defined in HRD Logbook:
You need to make that the selected database in QSO Relay matches the same database that is currently being used in HRD Logbook. I believe you should then be ready to go, as I was able to successfully synchronize all 1,754 contacts this time.
This is the new Delete Contact dialog that will be in the new release coming shortly. It displays the row count in the caption and also provides an incremental search by QsoDate or Call facility that will make it much easier to locate a row if the one you want to delete is not the most recent: