Does Dir() make any guarantee on the order of files returned?

The Problem (Q-score 8, ranked #59th of 95 in the VBA Core archive)

The scenario as originally posted in 2010

I am trying to clean up some existing code

Sheets("Control").Select
MyDir = Cells(2, 1)
CopySheet = Cells(6, 2)
MyFileName = Dir(MyDir & "wp*.xls")

' when the loop breaks, we know that any subsequent call to Dir implies
' that the file need to be added to the list
While MyFileName <> LastFileName
    MyFileName = Dir
Wend

MyFileName = Dir

While MyFileName <> ""
    Cells(LastRow + 1, 1) = MyFileName
    LastRow = LastRow + 1
    MyFileName = Dir
Wend

My question relates to how Dir returns results and if there are any guarantees on the order of results. When using Dir in a loop as above, the code implies that the resultant calls to Dir are ordered by name.

Unless Dir guarantees this, it’s a bug which needs to be fixed. The question, does Dir() make any guarantee on the order in which files are returned or is it implicit?

Solution

Based on @Frederic’s answer, this is the solution I came up with.

Using this quicksort algorithm in conjunction and a function that returns all files in a folder …

Dim allFiles As Variant
allFiles = GetFileList(MyDir & "wp*.xls")
If IsArray(allFiles) Then
    Call QuickSort(allFiles, LBound(allFiles), UBound(allFiles))
End If

Dim x As Integer
Dim lstFile As String
x = 1

' still need to loop through results to get lastFile
While lstFile <> LastFileName 
    lstFile = allFiles(x)
    x = x + 1
Wend

For i = x To UBound(allFiles)
    MyFileName = allFiles(i)
    Cells(LastRow + 1, 1) = MyFileName
    LastRow = LastRow + 1
Next i

Why community consensus is tight on this one

Across 95 VBA Core entries in the archive, the accepted answer here holds niche answer (below median) status — meaning voters are unusually aligned on the right fix.

The Verified Solution — niche answer (below median) (+6)

Advisory answer — community consensus with reference links

Note: the verified answer below is a reference / advisory response rather than a copy-ready snippet.

There’s no guarantee that Dir() will return the files in any particular order. The MS Access VBA documentation even says:

Tip Because file names are
retrieved in no particular order, you
may want to store returned file names
in an array, and then
sort the array.

When to Use It — vintage (14+ years old, pre-2013)

Ranked #59th in its category — specialized fit

This pattern sits in the 95% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the VBA Core archive for a higher-consensus alternative.

What changed between 2010 and 2026

The answer is 16 years old. The VBA Core object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.