When I've run into similar issues, both with DBPro and AppGameKit, they generally tend to fall into one of the following:
- Memory limitation, video and/or system RAM (capacity doesn't really matter, it's about how much consecutive memory is available for the required image operations).
- Some other third party display related program running in the background that blocks or otherwise interferes with the video memory needed to generated the bitmap font.
When a user sees some letters but not all, this reinforces the possibility that AppGameKit was not allowed to generate all of the required image indexes for font characters that it needed (that is, it was not allowed to access the video resources needed to generate the characters in memory in the background). They may see the same missing letters or the missing letters may vary every time they launch the game. Or the game may work fine for a while, then run into the problem later on as new memory limitations may occur on their system. Unfortunately, there can be a few possible causes which can vary from system to system. Insufficient or intermittently blocked memory tends to be a primary baseline cause though. And although I can't say for sure, it seems to be more frequent on systems that have integrated graphics architecture (ie Intel HD) where system memory is consumed for use as video memory, sometimes resulting in limitation problems for either memory pool or both. The way in which text characters are generated in memory seems to be particularly sensitive to that kind of limitation. It can be an early warning indicator of other memory problems later on as they play where crashing may occur.
For further troubleshooting, it can help to know what version of Windows they are running (and with 10, what build number), what specific GPU make and model they are using, and what specific display driver they are using. Knowing what other software they are running in the background can also help in some situations. If anyone is running GeForce Experience, ask them to turn that off entirely, then try again to test for changes. Likewise with any other display related programs (video recording, display enhancement, etc). If they are running an integrated system, shutting down other programs running in the background may help further. The goal is to maximize available memory resources and prevent interference.
There may be some kind of internal flaw in AppGameKit with how it generates text images relative to the display resolution being used, but if the problem is intermittent and/or gets better when a lower resolution is used (hence lowering the display/buffer memory used), that could indicate it's just out of memory. If someone is running a low resolution of something like 1366X768, this can indicate they are using some pretty old and likely limited graphics hardware that may have too much of a limitation on memory resources for your game. If so, the only solutions for them would be to sort out whatever interference problem may be in place, free up more memory resources, use a lower resolution, and/or reduce detail settings to use smaller core images for less memory overhead (if available in your game).
