If you experience general performance problems and sudden freezes while using DbVisualizer, it may be caused by some file system not being properly available or addressable. To verify, start DbVisualizer and then open the File->Open... dialog. If that takes unexpectedly long time, this guide is for you.
The workaround is to add the following Java property in Tools->Tool Properties under the General category:
The value 1000 in this example translates to 1000ms which is 1 second. You may need to alter this value in case you have slow but otherwise working file systems that are still of interest.