How can I resolve the "No Font Name" issue when importing fonts into R using extrafont?

Question

I have a folder on my Windows desktop (C:\Users\me\Desktop\Fonts) which contains fonts that I would like to import into R using extrafont.

When I try to import the fonts using

library(extrafont)
font_import(paths = "C:/Users/me/Desktop/Fonts", prompt=FALSE)

I receive the error message

Scanning ttf files in C:/Users/me/Desktop/Fonts ...
Extracting .afm files from .ttf files...
C:\Users\me\Desktop\Fonts\arista-light.ttf : No FontName. Skipping.
C:\Users\me\Desktop\Fonts\facebook-letter-faces.ttf : No FontName. Skipping.
C:\Users\me\Desktop\Fonts\Guardian-EgypTT-Text-Regular.ttf : No FontName. Skipping.
C:\Users\me\Desktop\Fonts\pico-black.ttf : No FontName. Skipping.
C:\Users\me\Desktop\Fonts\product-sans.ttf : No FontName. Skipping.
Found FontName for 0 fonts.
Scanning afm files in C:/Users/me/Documents/R/R-3.6.3/library/extrafontdb/metrics
Warning messages:
1: In system2(ttf2pt1, c(args, shQuote(ttfiles[i]), shQuote(tmpfiles[i])),  :
  running command '"C:/Users/me/Documents/R/R-3.6.3/library/Rttf2pt1/exec/ttf2pt1.exe" -a -G fAe "C:\Users\me\Desktop\Fonts\arista-light.ttf" "C:\Users\me\AppData\Local\Temp\RtmpOgbdTh/fonts/arista-light"' had status 1
2: In system2(ttf2pt1, c(args, shQuote(ttfiles[i]), shQuote(tmpfiles[i])),  :
  running command '"C:/Users/me/Documents/R/R-3.6.3/library/Rttf2pt1/exec/ttf2pt1.exe" -a -G fAe "C:\Users\me\Desktop\Fonts\facebook-letter-faces.ttf" "C:\Users\me\AppData\Local\Temp\RtmpOgbdTh/fonts/facebook-letter-faces"' had status 1
3: In system2(ttf2pt1, c(args, shQuote(ttfiles[i]), shQuote(tmpfiles[i])),  :
  running command '"C:/Users/me/Documents/R/R-3.6.3/library/Rttf2pt1/exec/ttf2pt1.exe" -a -G fAe "C:\Users\me\Desktop\Fonts\Guardian-EgypTT-Text-Regular.ttf" "C:\Users\me\AppData\Local\Temp\RtmpOgbdTh/fonts/Guardian-EgypTT-Text-Regular"' had status 1
4: In system2(ttf2pt1, c(args, shQuote(ttfiles[i]), shQuote(tmpfiles[i])),  :
  running command '"C:/Users/me/Documents/R/R-3.6.3/library/Rttf2pt1/exec/ttf2pt1.exe" -a -G fAe "C:\Users\me\Desktop\Fonts\pico-black.ttf" "C:\Users\me\AppData\Local\Temp\RtmpOgbdTh/fonts/pico-black"' had status 1
5: In system2(ttf2pt1, c(args, shQuote(ttfiles[i]), shQuote(tmpfiles[i])),  :
  running command '"C:/Users/me/Documents/R/R-3.6.3/library/Rttf2pt1/exec/ttf2pt1.exe" -a -G fAe "C:\Users\me\Desktop\Fonts\product-sans.ttf" "C:\Users\me\AppData\Local\Temp\RtmpOgbdTh/fonts/product-sans"' had status 1

Based on this I have two questions:

1. How can I overcome the No FontName. Skipping. issue?
2. What are the warning messages trying to tell me and do I need to be concerned about this?

I would appreciate any help, many thanks in advance!

Answer 1

As it was mentioned by @Moritz Schwarz, the problem is traced to Rttf2pt1.

According to a solution proposed here, downgrading it to 1.3.8 will fix the problem:

library(extrafont)
library(remotes)
remotes::install_version("Rttf2pt1", version = "1.3.8")
extrafont::font_import()