Ggtcf

I'm running the latest R version, 3.5.2 64-bit
the latest RStudio version, 1.1.463
and since today I suddenly run into the following problems:

1) RStudio gives an error ON STARTING UP: 'An error occurred while checking for updates. Unable to establish connection with R session.

2) It is slow on starting, it is slow on loading the workspace, and it is much slower to run code (working on R shiny app), and that seems to be true for all code files.

3) I get errors about the data.table packages:

Loading required package: data.table Warning in library(package,
lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE, :

there is no package called ‘data.table’

I already removed RStudio completely,

ran registry cleaner freeware,

reinstalled a new download of RStudio

updated all packages

removed all .Rdata files that I could find

reinstalled Rstudio again....

and rebooted the laptop several times in between.

still slow, and still the errors mentioned above...

I'm clueless what is going on beyond what I tried, does anyone have a clue?

Yesterday it was all working fine, and now it's not. I did not update anything today on my laptop, the routine is the usual, I start my R Shiny App that I'm working on, and this runs

if(!require('shiny')) install.packages('shiny')

for all packages I need for it.
As I said, it already goes wrong on starting RStudio, and all R code executions seem slow, not just my 1 app.

Memory usage by rstudio.exe *32 and rsession.exe are both around 300,000 K, so that doesn't seem to be unusual either.

here is my session info:

 sessionInfo()
R version 3.5.2 (2018-12-20)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

Matrix products: default

locale:
[1] LC_COLLATE=Dutch_Netherlands.1252 LC_CTYPE=Dutch_Netherlands.1252 
[3] LC_MONETARY=Dutch_Netherlands.1252 LC_NUMERIC=C 
[5] LC_TIME=Dutch_Netherlands.1252 

attached base packages:
[1] grid stats graphics grDevices utils datasets methods 
[8] base 

other attached packages:
 [1] flowPeaks_1.26.0 PerformanceAnalytics_1.5.2
 [3] xts_0.11-2 zoo_1.8-4 
 [5] gtools_3.8.1 lemon_0.4.3 
 [7] gridExtra_2.3 pryr_0.1.4 
 [9] scales_1.0.0 stringi_1.3.1 
[11] V8_2.0 taRifx_1.0.6.1 
[13] webshot_0.5.1 broom_0.5.1 
[15] forcats_0.4.0 stringr_1.4.0 
[17] dplyr_0.8.0.1 purrr_0.3.1 
[19] readr_1.3.1 tibble_2.0.1 
[21] tidyverse_1.2.1 randomForest_4.6-14 
[23] yaml_2.2.0 plyr_1.8.4 
[25] colourpicker_1.0 DT_0.5 
[27] tidyr_0.8.3 htmlwidgets_1.3 
[29] plotly_4.8.0 ggplot2_3.1.0 
[31] bit64_0.9-7 bit_1.1-14 
[33] lubridate_1.7.4 shinyWidgets_0.4.5 
[35] shinyjqui_0.3.2 shinyjs_1.0 
[37] shinydashboard_0.7.1 shinyBS_0.61 
[39] shiny_1.2.0 

loaded via a namespace (and not attached):
 [1] httr_1.4.0 jsonlite_1.6 viridisLite_0.3.0 modelr_0.1.4 
 [5] assertthat_0.2.0 cellranger_1.1.0 pillar_1.3.1 backports_1.1.3 
 [9] lattice_0.20-38 quadprog_1.5-5 glue_1.3.0 digest_0.6.18 
[13] promises_1.0.1 rvest_0.3.2 colorspace_1.4-0 htmltools_0.3.6 
[17] httpuv_1.4.5.1 pkgconfig_2.0.2 haven_2.1.0 xtable_1.8-3 
[21] later_0.8.0 generics_0.0.2 withr_2.1.2 lazyeval_0.2.1 
[25] cli_1.0.1 magrittr_1.5 crayon_1.3.4 readxl_1.3.0 
[29] mime_0.6 nlme_3.1-137 xml2_1.2.0 tools_3.5.2 
[33] data.table_1.12.0 hms_0.4.2 munsell_0.5.0 compiler_3.5.2 
[37] rlang_0.3.1 rstudioapi_0.9.0 crosstalk_1.0.0 miniUI_0.1.1.1 
[41] gtable_0.2.0 codetools_0.2-15 curl_3.3 reshape2_1.4.3 
[45] R6_2.4.0 knitr_1.21 Rcpp_1.0.0 xfun_0.5 
[49] tidyselect_0.2.5