Thanks for your note. One extra piece of information. View() opens a new tab in the Source pane of RStudio, but does not show any output, the new window is blank. View(1) works normally. See the image in Step 5 below.
Here are your tests (and some others that may be helpful).
Step 1: View
> View
function (...)
.rs.callAs(name, hook, original, ...)
<environment: 0x7f84ec5ebaf8>
Step 2: restart R > View >> same result
Step 3: sessionInfo()
> sessionInfo()
R version 4.0.2 (2020-06-22)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS Catalina 10.15.6
Matrix products: default
BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRlapack.dylib
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] datasets utils methods base
other attached packages:
[1] RMySQL_0.10.20 DBI_1.1.0
loaded via a namespace (and not attached):
[1] Rcpp_1.0.4.6 rstudioapi_0.11 magrittr_1.5 grDevices_4.0.2 tidyselect_1.0.0
[6] munsell_0.5.0 colorspace_1.4-1 R6_2.4.1 rlang_0.4.7 fansi_0.4.1
[11] dplyr_0.8.5 tools_4.0.2 grid_4.0.2 packrat_0.5.0 gtable_0.3.0
[16] cli_2.0.2 stats_4.0.2 ellipsis_0.3.1 assertthat_0.2.1 tibble_3.0.3
[21] lifecycle_0.2.0 crayon_1.3.4 purrr_0.3.4 ggplot2_3.3.0 graphics_4.0.2
[26] vctrs_0.3.2 glue_1.4.1 compiler_4.0.2 pillar_1.4.6 scales_1.1.0
[31] pkgconfig_2.0.3
Step 4: utils::View(iris)
> utils::View(iris)
Error in .External2(C_dataviewer, x, title) : unable to start data viewer
In addition: Warning message:
In utils::View(iris) : unable to open display
Step 5: View(1) <-- Works!!

Step 6: View(c(1,2)) fails.