Win32 CreateDirectory fails with multiple folders in a long path - delphi

Question

The environment is Windows 7 Pro and Delphi 7.
Windows.CreateDirectory() is failing to create multiple folders in a very long path that is well under the path length limit. GetLastError() returns ERROR_PATH_NOT_FOUND.
The failure is the same on an ESXi virtual machine, as well as a native Win7 workstation and physical disk. A similar failure occurs with Windows.MoveFile().
The long path in the code below is created correctly in a CMD window as a pasted parameter to MKDIR.
My work-around is creating this long path piece-meal. I split the path at the '\' character into a string array. Then I loop through the array and build the cumulative path from each element. The loop correctly builds the full path without an error.
I have no clue why the Win32 function fails to create a valid long path.
var
arrDstPath : TStringArray;
begin
// --------------
// failing method
// --------------
strDstPath := 'C:\Duplicate Files\my customer recovered data\desktop\my customer name\application data\gtek\gtupdate\aupdate\channels\ch_u3\html\images\';
if (Windows.CreateDirectory(pchar(strDstPath),nil) = false) then
Result := Windows.GetLastError; // #3 is returned
if (DirectoryExists(strNewPath) = false) then
Result := ERROR_PATH_NOT_FOUND;
// -----------------
// successful method
// -----------------
strNewPath := '';
LibSplitToArray(arrDstPath,'\',strDstPath);
for intIdx := 0 to High(arrDstPath) do
begin
strNewPath := strNewPath + arrDstPath[intIdx] + '\';
Windows.CreateDirectory(PChar(strNewPath), nil);
end;
if (DirectoryExists(strDstPath) = false) then // compare to original path string
begin
Result := ERROR_PATH_NOT_FOUND;
Exit;
end;

Answer 1

Actually, the official documentation for the CreateDirectory function describes what's going on. Since the function fails, your instinct should be to have a look at the section describing the return value, which states:
ERROR_ALREADY_EXISTS
The specified directory already exists.
ERROR_PATH_NOT_FOUND
One or more intermediate directories do not exist; this function will only create the final directory in the path.
I assume you got ERROR_PATH_NOT_FOUND, and the documentation suggests a probable reason: you are attempting to create several levels of subdirectories at once, which the function doesn't support.
Fortunately, the Delphi RTL has the ForceDirectories function that can create subdirectories recursively. (How can I Create folders recursively in Delphi?)
In Delphi 2010 and later, you can also use TDirectory.CreateDirectory from IOUtils.pas. Internally, this calls ForceDirectories.