Win1020H2, .NET Framework 4.8, invalid results from System.IO.FileInfo() and File.Copy()

Question

There is a bug in 20H2.NTFS or .NET Framework 4.8 System.IO.FileInfo() and File.Copy() (at least).

I wrote a C# program that walked the entire directory tree for a NTFS volume that had over 1.5M files. Once I had this list of files, I called System.IO.FileInfo on each one and found 166 files where FileInfo.Exists==false, which implies exactly what it says, that file does not exist. However, it does exist, I can see them with File Explorer, select Properties and get valid results, and I have verified their contents(a few are .MP4 and they play fine).

I figured there was some corruption in the NTFS tables, so I added recovery code to my program that was going to copy each file to \tmp, delete the original, then copy back (figuring this would create a fresh, valid entry).

However, the first File.Copy throws an exception, "Could not find a part of the path". All failures are crazy long paths, ex:
'Z:\backups\desktop\Cdrive\Program Files (x86)\Adobe\Adobe After Effects CS4\Support Files\Plug-ins\Effects\Synthetic Aperture(Color Finesse 2 Support)\Color Finesse 2\Color Finesse Presets\Gels\GamColor CineFilters\GamColor CineFilters_1-4 Plus Green.cfpreset'. I was suspicious of the 2nd set of parenthesis , "(Color Finesse 2 Support)". I renamed that directory, using File Explorer, removing the parenthesis , and now this file behaves normally!!!

Parenthesis are valid in directory and filenames. The files do exist and their contents are fine!!!

Obvious bug in NTFS or foundation classes!!!

Answer 1

Perhaps the white space in the path might be the issue. Try

Public Module LanguageExtensions
    <Runtime.CompilerServices.Extension>
    Public Function AddQuotesIfRequired(path As String) As String
        Return If(Not String.IsNullOrWhiteSpace(path), If(path.Contains(" ") AndAlso (Not path.StartsWith("""") AndAlso Not path.EndsWith("""")), """" & path & """", path), String.Empty)
    End Function
End Module

Usage

Dim somePath = "CS4\Support Files\Plug-ins\Effects\Synthetic Aperture(Color Finesse 2 Support)\Color Finesse 2\Color Finesse Presets\Gels\GamColor CineFilters\GamColor CineFilters_1-4 Plus Green.cfpreset"
Dim result = somePath.AddQuotesIfRequired()

Answer 2

OMG! Even this forum software, or the browser(I use Chrome), has a problem with this long string.

In what I originally entered, there is a slash between "Synthetic Aperture" and "(Color Finesse 2 Support)", BUT it doesn't display!!!

I copy/pasted that path in, but I thought it got lost somehow. NOPE! I checked twice with EDIT and the "\" is in the raw data, but the formatter, or the browser, doesn't display it!?!

It's very interesting because those parens around "(Color Finesse 2 Support)" is definetely the problem area because I removed them with RENAME from File Explorer and everything was happy and worked.