In order to manually delete all of those threads, I just deleted the Forum-node which contained all those many threads.
So now I thought to use "ACP > Tools > Cache" to rebuild my Forum and clear everything, but when doing so, it shows that my Forum is "rebuilding" about 14000 threads.
So are those 1000 threads (which I actually deleted by deleting the Forum-Node) still existing in the database ?
Where are the 14000 threads coming from ? Especially that my Forum is empty and does not contain 1 single thread.... ?
What is happening when "Rebuilding Cache" ?
Appreciate your help!