How to get rid of <U+FEFF> in a R data.table column name? -

in order import large dataset i've used data.table option integer64 = "character" because columns have large numbers truncated otherwise, , identifiers.

my <- fread("mydata.csv", encoding="utf-8",integer64 = "character") 

with option enabled columns imported characters have problem, columnnames have being automatically modified start these character

<u+feff> 

for example first column called

<u+feff>id_2006_2011 

the problem can't work names, example:

> minidt[1,"<u+feff>id_2006_2011", with=f] error in `[.data.table`(minidt, 1, "<u+feff>id_2006_2011", = f) :    column(s) not found: <u+feff>id_2006_2011 > minidt[1,"id_2006_2011", with=f] error in `[.data.table`(minidt, 1, "id_2006_2011", = f) :    column(s) not found: id_2006_2011 

how can work them? how can change them simpler? i've tried

setnames(minidt, "id_2006_2011", "id") 

but error:

error in setnames(minidt, "id_2006_2011", "id") : items of 'old' not found in column names: id_2006_2011

the column name there because...:

> minidt[1,1, with=f]    <u+feff>id_2006_2011 1:         160701000002 

for moment i'll using numbers instead of names refer columns.