Installer window keeps blank on a Mac

[Tiemo]

I am using for my program an installer, which is made with LiveCode. I codesign my program. This installer works fine since years, no current changes. But now I have a customer with OS X 10.9.5, where the installer window opens, but the window keeps blank. Neither the instructional text of the window, nore the buttons "Cancel" and "Next" show up, just a blank screen, only a blue background on a part of the window shows up. Only the window title and the close box appear correctly. So the customer can't install my program. The security setting on that machine is "allow install from all". We tried two versions, one from CD, one as a DMG from a download, both with the same behavior. My customers says, no anti virus program or other special security software is installed

Has anybody ever seen such a behavior of any program on a Mac? I have no idea left where to look for. Because it is only one single customer, I think it must be something going on on that Mac, but because the installer is made with LiveCode, I am asking it here too.

Ever seen such a behavior? Any idea what else to check for?

Thanks

[dunbarx]

Hi.

Have you tried running the app on another Mac with 10.9?

Craig Newman

[Tiemo]

yes on lots without any problems.
I thought perhaps this is a seldom, but known phenomenom, but obviosly it is a unique issue on this Mac.
Thanks