Been battling this for the last 4 hours. The error appeared after I updates RStudio and R and then persisted across all combinations of the recent 2018-2019 versions of RStudio and R. The reproducible example below.
RSTudio version: Version 1.2.1522
R version 3.5.2 (2018-12-20) -- "Eggshell Igloo"
Copyright (C) 2018 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64 (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
Microsoft R Open 3.5.2
The enhanced R distribution from Microsoft
Microsoft packages Copyright (C) 2018 Microsoft Corporation
Using the Intel MKL for parallel mathematical computing (using 8 cores).
Default CRAN mirror snapshot taken on 2019-02-01.
n <- 10
<simpleError in is(obj, "ore.frame"): could not find function "is">
I also have a new mouse wheel scrollign problem in the new rstudio but that's a story for another post.
Would appreciate any help! Thank you!