@dgoebel wondered if and how you resolved this? Or what @Mark_Ortmann suggests as the resolution?
I have uninstalled R 3.6.2 and KNIME 4.1.1 , restarted PC, reinstalled both of these but I get the same issue.
R path: C:\Program Files\R\R-3.6.2
I keep getting the following error: " R Version 3.5.0 and Rserve <= 1.8-6 currently have issues preventing their full use in KNIME. A future release of R and/or Rserve may fix these issues."
Then when running a script I then get āERROR R to Table 2:794 Execute failed: Could not detach connection to R, could leak objects to other workspaces.ā
I think it is highly recommended that you install RServe 1.8.6 on your machine, which is not as easy as one would think, my last successful attempt went like this:
Maybe you start with that if this does not help there could be more links to explore.