Exporting charts as Image sometimes generates empty files

Question

I'm doing a macro that exports all the charts in the sheet and then opens Outlook and attaches them. However, I've noticed, several times the charts do export but as 0KB (the file is created, but the image can't be seen)

But it doesn't happen to all the charts. Just most of them and sometimes, it generates them all without a problem. (When I execute the code step by step, all charts generate without a problem, also after executing the step by step, then I execute it normally and all charts generate, BUT if I close and reopen the workbook, it gives the same issue, generates only two and the rest are empty files)

Here's the code:

Dim sheetNumber, Size, i As Integer
    Dim chartNames(), FNames() As String
    Dim objChrt As ChartObject
    Dim myChart As Chart


    'Activate Charts Sheet
    Sheets("GRAFICAS").Activate
    'Calculate Number of Charts in Sheet
    Dim chartNumber
    chartNumber = ActiveSheet.ChartObjects.Count
    'Redimension Arrays to fit all Chart Export Names
    ReDim chartNames(chartNumber)
    ReDim FNames(chartNumber)
    'Loops through all the charts in the GRAFICAS sheet
    For i = 1 To chartNumber
        'Select chart with index i
        Set objChrt = ActiveSheet.ChartObjects(i)
        Set myChart = objChrt.Chart
        'Generate a name for the chart
        chartNames(i) = "myChart" & i & ".png"

        On Error Resume Next
        Kill ThisWorkbook.Path & "\" & chartNames(i)
        On Error GoTo 0
        'Export Chart
        myChart.Export FileName:=Environ$("TEMP") & "\" & chartNames(i), Filtername:="PNG"
        'Save path to exported chart
        FNames(i) = Environ$("TEMP") & "\" & chartNames(i)
    Next i

What am I missing?

Answer 1

It turns out, it's a random error for Excel 2010-2013 users. However, after some more googling. I encountered the answer here

You just need to add

objChrt.Activate

After selecting the chart. So In my case the final code looks like this:

 For i = 1 To chartNumber
        'Select chart with index i
        Set objChrt = ActiveSheet.ChartObjects(i)
        objChrt.Activate
        Set myChart = objChrt.Chart
        'Generate a name for the chart
        chartNames(i) = "myChart" & i & ".png"

        On Error Resume Next
        Kill ThisWorkbook.Path & "\" & chartNames(i)
        On Error GoTo 0
        'Export Chart
        myChart.Export FileName:=Environ$("TEMP") & "\" & chartNames(i), Filtername:="PNG"
        'Save path to exported chart
        'Application.Wait (Now + #12:00:01 AM#)
        FNames(i) = Environ$("TEMP") & "\" & chartNames(i)
    Next i