Hopeless: memory not being released

[Comintern]

One other thing to try would be to use a fixed size array. I'd bet that VB is leaking memory from the array allocations. Dynamic arrays have additional overhead in terms of memory allocations, and the redimensions may be the problem. BTW, the preserve keyword actually uses double the amount of memory because it actually copies the entire array into a new array in memory and then (in theory ) deallocates the previous one. If you think about it, it has to work this way to ensure that the new array gets a contiguous region in memory. There is no way of knowing if the additional addresses above the original allocation are free, so it plays it safe and just makes it bigger. You should be OK if you just avoid making memory operations inside your loop.

See if you can get something like this to work. I collapsed your loop a little bit.

Dim FullBuffer(BUFFER - 1) As Byte, j As Integer        'additional dims. Assumes BUFFER is a const.
    
    hFile = FreeFile
    
    Open Filename For Binary Access Read As #hFile
        For i = 1 To chunkNum
            'tells us how much is still to be read...
            If (i = chunkNum) Then
                tempChunkSize = lastChunkSize
            Else
                tempChunkSize = realChunkSize
            End If
            'get new filename
            sliceFileName = desPath & slicePrefix & Format$(i, formatStr) & "." & fileExt
            aFile = FreeFile
            'open file for write
            Open sliceFileName For Binary Access Write As #aFile
                Do While (tempChunkSize > 0)
                    'read and write
                    Get #hFile, , FullBuffer
                    If tempChunkSize >= BUFFER Then
                        Put #aFile, , FullBuffer        'write the whole thing.
                    Else
                        For j = 1 To tempChunkSize      'write each byte individually - only doing
                            Put #aFile, , FullBuffer(j) 'this once per file, so the overhead isn't
                        Next j                          'that much.
                    End If
                    'progress forward
                    tempChunkSize = tempChunkSize - BUFFER
                    PB1.value = PB1.value + 1
                    'Erase FullBuffer                   'try uncommenting this as a next step.
                Loop
            Close #aFile
            'let windows refresh etc.
            DoEvents
        Next i
    Close #hFile

[TupacShakur]

One other thing to try would be to use a fixed size array.
[...]
You should be OK if you just avoid making memory operations inside your loop.

People, forgive me for using this statement too much: ALREADY TRIED THAT ... It seems this is truely a hopeless case.

I'd bet that VB is leaking memory from the array allocations.

I'd bet VB is leaking memory from all over .

I collapsed your loop a little bit.

I tried this approach, but, as i expected, same problem is occuring. Thanks for ur help guys.