Knime 4.0 and SQL Server Legacy DB Reader

Hi Christopher,
Edited: Initially I said that it would be possible to upgrade from 3.7.x to 4.0 but I was wrong. You have to do a fresh installation with KNIME 4.0 since upgrading is NOT possible. Sorry about that.

You did install KNIME 4.0 new and then opened the old workflow with the new installation? Did you install in KNIME 3.7.2 the official Microsoft SQL Server driver? Unfortunately you need to explicitly install it for each KNIME installation due to license restrictions from Microsoft. In KNIME 4.0 you need to install the KNIME Microsoft JDBC Driver for SQL Server (legacy) (marked yellow in the image below) for the legacy connector node. If this is not installed KNIME uses the open source jTDS driver. The red marked extension is the same driver but for the new database framework (all db nodes without (legacy) at the end).
Can you please double check if it is installed. To check go to File->Install KNIME Extensions… and search for sql server (see below). If you see the entries please install them. If you don’t see them and the Hide items that are already installed option is enabled they are already installed.

If the extensions are installed, could you please post the error message in the forum or send it so me via personal mail if it contains sensitive information.