App wont run on one machine

I have one customer who cannot run my app on their WIndows 7 service pack 2 machine, with an NVIDEA GFX card, bags of memory and disc space.
Virus checkers all turned off.
The program starts, can display messageboxes, but any attempt to open a document window causes the app to simply vanish from the task list.
No errors reported in the log file that handles unhandled exceptions.

Windows reports it has stopped working and suggests looking at

which are basically just a list of DLLs and dates.

An earlier version compiled in 2015 works fine.
(The current build of the app is being installed and used by several new customers each day/week)

Any ideas?

If possible, ask the customer to run SysInternals DebugView to get details. It is available on MS Technet. The customer may also get some information from the Windows event viewer.

For what it is worth, I don’t believe that there was ever a Windows 7 SP2. Sometimes the convenience pack was called SP2, but it is not an SP as such.Perhaps the customer can authorize that you access his computer through Windows remote desktop, you would be able to trouble shoot yourself. A better solution even would be GoToMyPC. The free trial would probably be sufficient to trouble shoot this customer. The client would be able to see everything that you do, contrary to remote desktop that would cut his connexion.

Could this be connected to
Have you tried to compile the app under Windows? In my case this was the solution.

I always do.

Seems the versions I created with Xojo 2014 and 2015 dont work.
Those created with (?) 2013 do, but I have deleted the 2013 edition now.
It may be the compiler, or code changes since 2014

Been there… 2.5 hours later I came here in desperation, after playing with virus checker, firewall, screen resolution, graphics acceleration, permissions…

I know that Avast and other virus checkers can get biblical on apps they dont have in their little lists.
But that doesnt cover why a version from 2 years ago works, and one from this year doesnt.
The windows which are opening dont do anything fancy and nothing that I can think of has changed in a way that would upset Win7.
Its a huge mystery.

Windows 7 is getting very difficult to support. I very seldom hear from Windows 8 and 10 users.

Just a few things off the top of my head:

Check that there aren’t any optional windows updates pending.

This “document window” you cant open, what controls are on it?

Are their nvidia graphics drivers up to date?

What version are you compiling with?

Check that there aren’t any optional windows updates pending. -requested

This “document window” you cant open, what controls are on it?

-first window was htmlviewer, checkbox, button
after coding that out for a ‘special build’, the next one would have been
-listbox, buttons, killertoolbar, scrollbars, timers

Are their nvidia graphics drivers up to date? -requested they look into that. I think this is the actual issue, but was hoping that just turning off acceleration would have done the trick.

What version are you compiling with?

Shipping version (works on everyone else’s machine) compiled in 2014
Waiting to hear about a build done in 2015

The ‘older version’ of the app which works , may have been compiled in 2013 or Realbasic 2012, but I don’t know how to tell.

Also ensure they have KB2670838 in their list of updates.

Does a blank Window1 test app open and display on their computer?

If that works, whip up a 20+ window test app with a new control on each window, put a button at the bottom of each window that will open the next, see when/if it blows up.

Good ideas. Thank you.