VBA userform is "Not Responding" while macro is running - vba

Question

Why my userform shows "Not Responding" when I run the following code? I have been trying to resolve it, but it is not resolved yet.
Actually it works sometimes. I think the problem has something to do with the screen updating.
' The input button in Sheet1
Sub Rectangle1_Click()
'Remember time when macro starts
StartTime = Timer
' To improve speed and performance
Application.ScreenUpdating = False
Application.EnableEvents = False
Application.Calculation = xlCalculationManual
' Show the userform
UserForm1.Show vbModeless
UserForm1.Label1.Caption = "Calculation in progress ... " & vbNewLine & "Please be patient"
UserForm1.Label1.Font.Size = 12
UserForm1.Top = (Application.Height / 2) - (UserForm1.Height / 2)
UserForm1.Left = (Application.Width / 2) - (UserForm1.Width / 2)
UserForm1.CommandButton1.Visible = False
UserForm1.Repaint
Call Insert_RawData
'Determine how many seconds code took to run
SecondsElapsed = Round(Timer - StartTime, 2)
UserForm1.Label1.Caption = "This code ran successfully in " & SecondsElapsed & " seconds"
UserForm1.CommandButton1.Visible = True
' Return back to the original settings
Application.ScreenUpdating = True
Application.EnableEvents = True
Application.Calculation = xlCalculationSemiautomatic
End Sub

Answer 1

It could be a number of things. If the issue is intermittent like you mention, then in all likelihood the program IS working, and Windows is just labeling it non-responsive because the program is working too hard to respond to the OS.
The likely issue is probably one, or a combination, of the following:
The amount of data being processed by Insert_RawData
The amount of data in the workbook(s) open when the macro is running
Insert_RawData is encountering an error due to a bad/unhandled value in one of the cells it works with (less likely)
Some suggestions to try and narrow the source down:
If there's a way to consistently run so that you get the "Non-Responsive" in the Excel window, insert a break point at the call to Insert_RawData and watch it run to see if it's hitting an error
Alternatively, try to put some error checks into Insert_RawData and break points on the code handling the case that the error check fails
Capture the amount of data processed (bytes, cells, whatever is easiest) during each run of the macro along with the run time & see if there's a threshold your hitting (ex. <= 1 GB runs fine, but >1GB and the application looks frozen)
Unless you are hitting an error in Insert_RawData though, it's likely that the macro WILL complete, it just might take a really long time.