MsgBox / popups freezes Excel

3600 lines of code sounds... ineffecient.
Do you turn off events and screenupdating etc while running the code to speed it up?

Can you give an example of code that will definitely crash after a few times?

The code could definitely be more efficient, but a lot of code is unavoidable - there's around 25 different functions that need to be performed, each ranging from several lines to up to around 700 lines of code for the largest.

An example of where it gets stuck is the following: (you can see it turns off events, screenupdating, etc.). This might run around 6-7 times at best, or sometimes just 3-4 times before it crashes with the popup. The popup in this case is right at the beginning of the code. This particular macro is around 400 lines of code.

Sub importDataCustom()
Dim bEvents As Boolean
Dim bAlerts As Boolean
Dim CalcMode As Long
Dim bScreen As Boolean

' save current settings
bEvents = Application.EnableEvents
bAlerts = Application.DisplayAlerts
CalcMode = Application.Calculation
bScreen = Application.ScreenUpdating

' disable events, alerts, automatic calculation & screen updating
With Application
.EnableEvents = False
.DisplayAlerts = False
.Calculation = xlCalculationManual
.ScreenUpdating = False
End With

LoadVars 'this runs another Sub of 50 lines of code, which grabs various variable values from the current sheet

Dim categoryNames(500) As String
Dim indicIDArray(0 To 10000, 0 To 1) As String
Dim categoryNamesCounter As Integer
Dim indicIDCounter As Integer

ProgramWorkbook = ActiveWorkbook.Name
DataFile = Application.GetOpenFilename("Data files, *.*", , "Please select a file containing the data you wish to import.")
If DataFile = False Then
End
End If

...freezes with this popup

Thanks, I will give that a go!

Just to let you know that this appears to have resolved it, so thanks very much for your help! I had to do that for every single popup. Now I just have Excel freezing when there is an error in the code - so an unexpected popup.

Thanks for that solution. It's a pity it loses the line number of the regular error message though. Do you know if it is still possible to show the regular error message with the debug button, in order to go to the line where the error occurs?

In my case the freeze is not a result of an error. imho it is purely related to the MsgBox that should be brought up. No fancy code around it.
I get my error in several excel files with completely unrelated code. The common part is "Show me that MsgBox"

I could find one stupid and not guaranteed way around it:
- Open Windows Taks Manager,
- kill dwm.exe and
- wait until my screen refreshes.
- Next, try to be with your mouse cursor in the area where the MsgBox shall be and start to click franticly... IF you hit one of the (hidden? or freshly popped up?) MsgBox buttons, then the macros run further.
Sometimes I have to kill dwm.exe multiple times to pass this blocking stage.
It looks to me that the MsgBox is 1. not popping up 2. stays invisible 3. ...???

I also have tried to implement the MsgBox using a timeout timer... thinking it IS there, but not accessible, but even in that case the MsgBox is not brought up and the timer doesn't start to run. (found that code on stackoverflow and it works fine... but it doesn't solve the problem I describe here, also that code blocks (display-a-message-box-with-a-timeout-value))

Anybody experiencing this thing and has a good explanation and/or solution to it?