Just updated to the newest RStudio release and running into this problem exactly as described by this post on the RStudio support site from a couple months ago:
View() takes a very long time to open a new tab to view a data frame, upwards of 20 seconds on the wall clock. This happens regardless of the data frame source (e.g., mtcars, ggplot2::diamonds, or one I've generated myself) or length (mtcars is just 32 rows, diamonds is 53,940). It happens regardless of whether one manually types View(mtcars) or clicks the data frame view icon in the Environment panel. The prompt immediately reappears (so system.time() doesn't return the inflated time), but the R session is still blocked (running another command will wait until the View() tab opens).
This seems to be a Windows 7 issue as I haven't seen any reports from other OS and it runs fine on my Mac at home.
Any insight from the RStudio team on this? I love the new features in 1.1, but can't start using it until this bug is resolved. Session info below.
> sessionInfo() R version 3.4.2 (2017-09-28) Platform: x86_64-w64-mingw32/x64 (64-bit) Running under: Windows 7 x64 (build 7601) Service Pack 1 Matrix products: default locale:  LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252  LC_MONETARY=English_United States.1252 LC_NUMERIC=C  LC_TIME=English_United States.1252 attached base packages:  stats graphics grDevices utils datasets methods base loaded via a namespace (and not attached):  compiler_3.4.2 tools_3.4.2 yaml_2.1.14