r - Issues after loading both plyr and dplyr, even in correct order -

note: have reviewed workarounds in this post, none seem work unless reboot r, impractical given sourcing sequence of r scripts , stopping after every script reboot r not viable solution.

i have issue seems being caused fact can't 'properly' detach plyr , dplyr package.

even if write following code:

detach("package:dplyr", unload = true) detach("package:plyr", unload = true) 

upon running:

library("plyr") library("dplyr") 

i following message:

you have loaded plyr after dplyr - cause problems. if need functions both plyr , dplyr, please load plyr first, dplyr: library(plyr); library(dplyr)

further if try using group_by function following error:

error in grouped_df_impl(data, unname(vars), drop) : object 'dplyr_grouped_df_impl' not found

this error doesn't appear if run code after rebooting r, since, seems, dplyr package doesn't seem need detached initially.

other things have tried:

• dplyr::group_by() (instead of group_by())
• reinstalling r
• reinstalling packages
• testing same code on computer, errors not repeat themselves

any guidance on might going wrong here , else try appreciated