Here’s a very simple utility that recursively finds uppercase file extensions and makes those who are lowercase. For once, it’s not written in C# but in good old DOS.
If you paste this code in a CMD file, you’ll have a working program. If you execute this cmd, it will take the current folder as the root and it will process all files and subfolders.
for /f "Tokens=*" %%f in ('dir /l/b/a-d') do (rename "%%f" "%%f") for /r /d %%x in (*) do ( pushd "%%x" for /f "Tokens=*" %%f in ('dir /l/b/a-d') do (rename "%%f" "%%f") popd )
Nowadays you would use PowerShell but this is a way to provide a quick fix to your users.