We only support using our components with a MySQL database. Akeeba Backup will install but not work on MS SQL Server because there is no equivalent to SHOW CREATE TABLE. All of our other software has not been tested with MS SQL Server and don't even have the necessary SQL sstatements to install their database tables.
This is the case with most Joomla! components; they only support MySQL or have very limited support for MS SQL Server. If you migrate your site to MS SQL Server you'll quickly find out that you have to use just the core Joomla! extensions or write everything yourself, from scratch. Please do remember that Joomla!'s support for MS SQL Server and other non-MySQL databases is not meant to be used by consumer websites, but enterprise-grade websites. On such websites it is customary to build everything from scratch and the reason for using MS SQL Server is that the CTO has already paid a gazillion dollars to Microsoft for the privilege of having a couple of database servers (as opposed to paying pennies on the dollar to Oracle and get professional MySQL cluster consultancy with the same effect). Basically, MS SQL Server support is three parts Joomla! doing some hell of a PR ("Microsoft contributes to Joomla!, all rejoyce!") and one part supporting enterprise clients. It's not something that you should be considering using on your own site.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!