Access denied in RenameFile after FileExists - delphi

Question

I´m regularly importing files from a path into an application with Delphi 10.2. After each successful import I want to move the current file to a new path(SuccessPath). It´s possible to have file names that already exist in the SuccessPath. That´s why I first check if the file name exists. If thats the case I append an index to the filename (e.g. test.txt changes to test_2.txt).
In some cases RenameFile returns false and GetLastError returns Access denied. It´s probably an unclosed file handle. Do I need to close a handle after calling FileExists? How would I do so?
Here´s my example code:
procedure TDemo.Execute;
begin
MoveFileWithRenameDuplicates('C:\temp\test.txt', 'C:\temp\new\');
end;
procedure TDemo.MoveFileWithRenameDuplicates(oldFile, newPath: string);
var
lNewFile: string;
i: integer;
begin
lNewFile := newPath + TPath.GetFileName(oldFile);
i := 0;
repeat
if FileExists(lNewFile) then
begin
i := i + 1;
lNewFile := newPath + TPath.GetFileNameWithoutExtension(oldFile) + '_' + IntToStr(i) + TPath.GetExtension(oldFile);
end;
until not FileExists(lNewFile);
WriteLn('lNewFile=' + lNewFile);
if not RenameFile(oldFile, lNewFile) then
WriteLn(SysErrorMessage(GetLastError));
end;

Answer 1

I changed my loop like Remy suggested. I also realized that the appended index didn´t actually increment so I changed that aswell:
procedure TDemo.MoveFileWithRenameDuplicates(oldFile, newPath: string);
var
lNewFile: string;
i: integer;
begin
lNewFile := newPath + TPath.GetFileName(oldFile);
i := 0;
while not RenameFile(oldFile, lNewFile) do
begin
if FileExists(lNewFile) then
begin
lNewFile := newPath
+ TRegEx.Match(TPath.GetFileNameWithoutExtension(oldFile), '/^(?''name''[^_]*)_\d*$', [roIgnoreCase]).Groups['name'].Value
+ '_' + IntToStr(i) + TPath.GetExtension(oldFile);
end
else
begin
WriteLn(SysErrorMessage(GetLastError));
break;
end;
end;
end;
This seems to have fixed my problem.