When I reinstalled the R package in r4.0，I found an ERROR.

** R
** byte-compile and prepare package for lazy loading
Error: object ‘is.factor.ff’ is not exported by 'namespace:ff'
Execution halted
ERROR: lazy loading failed for package ‘ffbase’
* removing ‘/home/tianaw/miniconda3/lib/R/library/ffbase’

The downloaded source packages are in
‘/tmp/RtmpT2wM3V/downloaded_packages’
Updating HTML index of packages in '.Library'
Making 'packages.html' ... done
Warning message:
In install.packages("ffbase") :
  installation of package ‘ffbase’ had non-zero exit status

I would like to be told how to solve this problem. Thank you.

This seems to be because of a change in the 'ff' package, which was updated on July 30 (https://cran.r-project.org/web/packages/ff/index.html). The change seems to have broken the ffbase package, and the ffbase package hsa not been updated, including on github (https://github.com/edwindj/ffbase)

Perhaps you should contact the ffbase maintainer to ask for an update. The maintainer is listed at https://cran.r-project.org/package=ffbase.