I recently added some basic audio to the game I'm working on. Just one sound effect. That works fine. But I noticed on uninstall_system it hangs for several seconds.

If I uncomment a call to al_reserve_samples, the hang goes away. I'm reserving 16 samples by the way. Also I am initializing audio and the audio codec addon and setting my default mixer beforehand.

On version 5.1.13 / Windows 10

This is totally anecdotal, but I haven't noticed the same on Allegro 5.2.0 64 bit on Windows 10 (but I am referencing through Java binding, and only using al_reserve_samples(1)). Since you are using 5.1.13, you could try using the latest version?

5.2 includes some deadlock related fixes for the audio addon, although I don't recall how to reproduce them.

I tried upgrading to 5.2, but unfortunately the issue is still presenting.

Ok, interesting. Does a simple program which just initializes everything, reserves some samples and calls uninstall system (if you call it in your game) hang?