64 bit Windows has more or less 'taken over the scene' from 32 bit Windows since the introduction of Windows 7 and recent hardware systems with 64 bit CPU's and 4 GB (or more) RAM. This may cause various issues with ODBC-enabled programs/applications (such as SQLyog).
To understand this we have to consider the complete 'stack' consisting of 1) the Operation System 2) the ODBC driver and 3) the application. On 32 bit Windows the complete stack is all 32 bit and no conflicts will arise. On 64 bit Windows both the ODBC-driver and the application may be 32 bit. Some vendors provide both 32 bit and 64 bit drivers and some only 32 bit. Since version 11 SQLyog is available as both 32 bit and 64 bit.
The two typical problems with ODBC and a 'mixed-bit stack' and SQLyog 32 bit (or any 32 bit application) are:
1)(Please note that this particular point applies to older Windows verssion (such as Win7) only. In newer Windows versions (such as Win10) both 32 bit and 64 bit ODBC drivers can be managed from the Windows Control Panel, as there is an entry/"Control Panel applet" for each type of driver). After installing a 32 bit ODBC driver it does not show up as an option when configuring a DSN from Control Panel .. Administration .. Data Sources. The reason is the ODBC manager launched from Control Panel is a 64 bit version of the ODBC manager that handles 64 drivers only. 64 bit Windows does however ship with a 32 bit version of the ODBC Manager. It is in the folder {System_Drive}:\Windows\SysWOW64 and is named 'odbcad32.exe'. To create a DSN using a 32 bit driver navigate to this folder (from command line or from Windows Explorer) and launch odbcad32.exe. Now you will see the 32 bit driver you installed show up properly and you can configure a functional DSN.
2) If you want to use a 64 bit driver with a 32 bit application like SQLyog, the DSN will have to be configured as a 'user DSN'. A 'system DSN' will not work in this environment. As a consequence a scheduled job will have to run with the privileges of the user that configured the DSN.
When using SQLyog 64 bit (or any 64 bit application) a 64 bit ODBC driver is required. A 64 bit Windows binary cannot utilize a 32 bit ODBC driver. If only 32 bit drivers are available for your data source(s) you will need to use SQLyog 32 bit. This applies for instance to Microsoft Office up to and including the 2010 version that was only available as 32 bit and only shipped with 32 bit drivers. But note that you can have both SQLyog 32 bit and 64 bit installed at the same time and can use the 32 bit version merely for migrating from ODBC data sources where only 32 bit drivers are available and use the 64 bit version for all other uses. Multiple SQLyogs installed on the same system will (unless the -dir switch is used) share all files in user's User Profile (all settings inclduing saved connections).
Additionaly users of Microsoft Office 64-bit editon may need to download the 64-bit version of the access database engine from this link (this package will work with Office 2010 and higher). This database engine is not shipped with all MS Office 64 bit installation packages, but is provided for free by Microsoft as a separate download.