(Yes, I'm answering my own question, to record my solution)
I should also note, in addition to above, I couldn't use the SQL Native Client driver either.
In the registry, under HKLM\SOFTWARE\ODBC the \ODBC.INI branch contains any defined connections, and the \ODBCINST.INI contains records for the installed drivers.
I checked a similar development machine, and my ODBCINST.INI was missing A LOT of entries. I blame the ccleaner application that was recently used to clean up my system of junk.
After exporting the registry branch from the other computer, and importing over my existing keys, everything worked again.
Below are some of the core records, to generate a .reg script. You should get the full list from a similar machine to yours.
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI]
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\Microsoft Access Driver (*.mdb)]
"UsageCount"=dword:00000002
"Driver"="C:\\WINDOWS\\system32\\odbcjt32.dll"
"Setup"="C:\\WINDOWS\\system32\\odbcjt32.dll"
"APILevel"="1"
"ConnectFunctions"="YYN"
"DriverODBCVer"="02.50"
"FileUsage"="2"
"FileExtns"="*.mdb"
"SQLLevel"="0"
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\Microsoft Access Driver (*.mdb, *.accdb)]
"UsageCount"=dword:00000003
"Driver"="C:\\PROGRA~1\\COMMON~1\\MICROS~1\\OFFICE12\\ACEODBC.DLL"
"Setup"="C:\\PROGRA~1\\COMMON~1\\MICROS~1\\OFFICE12\\ACEODBC.DLL"
"APILevel"="1"
"ConnectFunctions"="YYN"
"DriverODBCVer"="02.50"
"FileUsage"="2"
"FileExtns"="*.mdb,*.accdb"
"SQLLevel"="0"
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\Microsoft Excel Driver (*.xls)]
"UsageCount"=dword:00000002
"Driver"="C:\\WINDOWS\\system32\\odbcjt32.dll"
"Setup"="C:\\WINDOWS\\system32\\odexl32.dll"
"APILevel"="1"
"ConnectFunctions"="YYN"
"DriverODBCVer"="02.50"
"FileUsage"="1"
"FileExtns"="*.xls"
"SQLLevel"="0"
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb)]
"UsageCount"=dword:00000003
"Driver"="C:\\PROGRA~1\\COMMON~1\\MICROS~1\\OFFICE12\\ACEODBC.DLL"
"Setup"="C:\\PROGRA~1\\COMMON~1\\MICROS~1\\OFFICE12\\ACEODEXL.DLL"
"APILevel"="1"
"ConnectFunctions"="YYN"
"DriverODBCVer"="02.50"
"FileUsage"="2"
"FileExtns"="*.xls,*.xlsx, *.xlsb"
"SQLLevel"="0"
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\SQL Native Client]
"UsageCount"=dword:00000001
"Driver"="c:\\WINDOWS\\system32\\sqlncli.dll"
"Setup"="c:\\WINDOWS\\system32\\sqlncli.dll"
"APILevel"="2"
"ConnectFunctions"="YYY"
"CPTimeout"="60"
"DriverODBCVer"="09.00"
"FileUsage"="0"
"SQLLevel"="1"
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\SQL Server]
"UsageCount"=dword:00000002
"Driver"="C:\\WINDOWS\\system32\\SQLSRV32.dll"
"Setup"="C:\\WINDOWS\\system32\\sqlsrv32.dll"
"SQLLevel"="1"
"FileUsage"="0"
"DriverODBCVer"="03.50"
"ConnectFunctions"="YYY"
"APILevel"="2"
"CPTimeout"="60"
You probably don't need to download new drivers, you just need to use the 32 bit version of the ODBC administrator found in:
%windir%\syswow64\odbcad32.exe
The ODBC administrator in the control panel is the 64 bit version which won't show any 32 bit drivers. If your application is 32 bit then you need a 32 bit dsn created in the 32 bit ODBC administrator.
Best Answer
There are number things to check, the first and foremost thing you want to do is create in your application what we call a persistent connection. A persistent connection simply means that somewhere in your startup code, you open up a table from the back end to a record set, and keep it open for the duration of any other operations you do in that application.
The reason why a persistent connection often makes a huge difference is that the newer operating systems tend to do have a tremendous amount of additional security and overhead when a connection to the databases created. And it turns out that generally opening and closing tables in access databases requires that these connections are also opened and closed. If you force the persistent connection to remain open at all times, then this very slow and large overhead process that interferes with general performance of general updates in your code will now not be incurred.
Give the above a try, since this setup very often cure is this performance issue and problem.