Issue with R6: error message says: there is no package called 'R6'

[nszekeres]

Hello, trying to "preview" a document in markdown, and keep getting this issue:

Error in loadNamespace(j <- i[[1L]], c(lib.loc, .libPaths()), versionCheck = vI[[j]]) :
there is no package called 'R6'
Calls: ... loadNamespace -> withRestarts -> withOneRestart -> doWithOneRestart
Execution halted

Any ideas on how to resolve?
FYI, I removed R and Markdown and reinstalled... it told me "success" but is still not allowing me to preview a document in html or word.

[gaborcsardi]

there is no package called 'R6'

Did you try installing the R6 package?

[nszekeres]

Thanks, now embarrassed. I surfed around and tried it again and it worked -- install.packages('R6') -- thank you.