Cannot automatically open pdf file with sumatra when using r-studio installed by anaconda

I installed rstudio via anaconda in win 10.

When I knitr my R markdown file, it is opened only when I choose "Preview PDF after compile using: Rstudio viewer". That is, if I choose to use "System viewer" or "Sumatra" the file is not opened automatically. It does nothing after creating the file.

I've checked that "sumatra.exe" is there under the correct path and it works find.

It's strange since when I used the normal desktop version of Rstudio, it does previewer pdf files with sumatra. But after I change to use Rstudio from anaconda, it fails to do so...

Since Rstudio viewer is not as efficient as sumatra on windows, i would like to know how to solve it.

Sorry, but the RStudio team doesn't provide support for Anaconda R / RStudio installations.