I can't read CSV files due to unavailable resource

I am reading 2000 CSV files as (my system is 32 GB RAM)

lapply(files, read_csv,col_names = TRUE,col_types = cols())

Each CSV file is around ~25 Mb. Earlier, I was able to read up 20Gigabyte.
Right now, I am not able to read more than 3Gb.
It shows an error with

Error: Resource temporarily unavailable

I restart the session using ctrl+shift+F10 to free the memory. It does not work at all.
If you have any suggestions. I would be very thankful.

Thank you

2,000 files averaging 25 MB is 50 GB. So that's not going to work. (Although internal and external storage may not be the same size.)

As a start, clear out your environment...don't just restart the session.

Then you might break files down into groups of 200 files and process one group at a time. After each group, clear out anything you don't need.