Me or is it thunder not beeing updated to work with the latest service pack. Markus
We are currently preparing a new version of Thunder that adds support for the 6.1 SP2. When a new Sitefinity version is released, we need at least one day to launch a new Thunder version, do some testing and make sure that everything is working as expected.
I am really sorry for this inconvenience but we are dependent of the release of Sitefinity when adding support for the new CMS version. We can't prepare a new build for Thunder until we are given a green light.
The new Thunder version with support for Sitefinity 6.1 SP2 is online.