Hello Patrick
A simple addition to the suggestion that Sam R proposed as a
last resort: using App.DoEvents.
In some situations this is still possible, especially if your
app does not process other events in general.
I tried this for a long running disk-searching app, and with a call
to App.DoEvents(20), a small value, this worked and allowed
updating of the Progressbar in my app without problems.
You could simply try it for a small project and see if it is
usable and safe in your case.
The pitfalls that might occur are similar to the usage of
(Win)ProcessMessages in Delphi (and C++ Builder ?) and
the like.
A nice description of the kind of situations in which problems
might occur are described in the following link, assuming that
you are familiar with Pascal code:
https://www.thoughtco.com/dark-side-of-application-processmessages-1058203