I wanted to download the game "steep" with steam and got a false positive virus alert by avira on the file "shadercontainer_engine_win64_f.dll". avira quarantined it - so I set exclusion rules for the file and tried again. for some reason steam could not create a file with the same name.
I tried for myself - I couldn't create the file as well. I deleted the folder which was containing the download. restarted the download - same problem.