5th Feb 2010 19 Aug 2011) - There is beta driver download available OLEDB provider – Microsoft Access Database Engine 2010 Redistributable – http://www.microsoft.com/downloads/details.aspx?familyid=C06B8369-60DD-4B64-A44B-84B371EDE16D&displaylang=en
Simple Answer – There is no 64 bit version of DAO provider, Jet OLEDB provider or ODBC driver – it is just 32 bit version of the provider which runs in wow64 mode.
1. 64 bit SSIS/ETL tool package trying to access Access/Jet database natively using 64 bit drivers.
2. 64 bit native applications (forms/console apps) natively accessing the database.
3. 64 bit native open source frameworks (rails/python based stuff) trying to access the database through regular ado/odbc provider/driver. (lookup the favourite support dl – sorry I do not have answers to adodbapi, odbcmx etc etc…)
4. For pure asp.net applications follow advice of Ken tucker (MVP).
Workaround : One needs to create/use 32 bit application in wow64 mode to ensure 32 bit jet oledb provider can be used. In simple words – just change the compile target to x86 in Visual studio or make file.
Project Settings ->Build ->Platform target -> change the target to x86.(you can accomplish the same with command line too with /platform option)
[update]To deal with SSIS’s rude behavior on 64 bit – check out the /X86 option to execute package on commandline. Also ensure Run64BitRuntime is set to false in the the metadata.
Brute force alternative (Update) – Use Corflags.exe as last option in dire circumstances for “just trying it out”. This only works for .net images/assemblies. No hex editing please :), not supported.
There is no 64 bit version of jet driver (hopefully they do as most of the machines will be 64 bit, it will look pretty odd to have to use this trampoline and not being able to do true migration – not everybody will like to migrate to sqlexpress).
Detailed – x64/x86/Wow explaination is available here.
Update(5th Feb 2010) - There is beta driver download available – http://www.microsoft.com/downloads/details.aspx?familyid=C06B8369-60DD-4B64-A44B-84B371EDE16D&displaylang=en
Official statement(5th Feb 2010) – http://blogs.msdn.com/psssql/archive/2010/01/21/how-to-get-a-x64-version-of-jet.aspx