Title says it all.
I am simply trying to keep track of time

double startTime = al_get_time(); <-- Crash because al_get_time() returns -6.0120304019-18e etc.
(This is in my IntroState constructor)

in my timed logic, though it doesn't really has anything to say as it never reaches this point.
if (al_get_time() - startTime >= 5.0) {
nextState = STATE_MENU;
}

Never had this issue before, and this very same program, that hasn't been changed since actually worked yesterday.
Been looking for hours for a solution, can't find one..
I am so confused

No I don't use globals, been trying for days now, still an error.
Still looking for solution.

I initialize everything before trying to use any allegro functions.
I don't use globals.
Etc.. I follow everything that must be done.

Here's code.

GameState.h

IntroState.h

If al_get_time() is returning insane values, that's usually because you've called it before initializing Allegro. That doesn't appear to be the case here though, so it's definitely weird.

I see global variables though.

From my experience, when al_init fails, it's usually because of a version mismatch between the headers compiled against and the dll in use. Allegro does a version check on start up inside al_init that will fail if the runtime is different from the headers used.

Looking at that code and what you posted above, you're definitely calling al_init() before al_get_time(), so not sure why you're getting insane values. The only thing I can think of is that initialization is failing behind your back (as mentioned above, you aren't checking the return value of Initialize() ).

if(!display = al_create_display(640,480)) {
   return 0;
}

I would just change your original code you posted for this to...

if(display == NULL) {
   return -1;
}

You're also making the same mistake with your font loading...

arial = al_load_font("arial.ttf", 12, 0);
if (!arial) {
   al_destroy_font(arial);
   exit(-1);
}

You're trying to destroy the arial font, but that is only needed if you successfully loading it in the first place. If loading fails, than there is nothing to destroy, no need to call that. Just use

arial = al_load_font("arial.ttf", 12, 0);
if (arial == NULL) {
   exit(-1);
}

As for your main problem, according to the online docs (https://www.allegro.cc/manual/5/al_get_time): "The return value is undefined if Allegro is uninitialised."

Looking at your code, I see a problem right away... what is this...

int Initialize(ALLEGRO_DISPLAY *&display, ALLEGRO_EVENT_QUEUE *&event_queue, ALLEGRO_TIMER *&timer);

You have *&display? ? You only need &display in C++ or *display but not both.

So the problem is that Allegro is not being initialized properly.

So your function prototype should be...

int Initialize(ALLEGRO_DISPLAY &display, ALLEGRO_EVENT_QUEUE &event_queue, ALLEGRO_TIMER &timer);

and in main() you should have...

ALLEGRO_DISPLAY *display;
ALLEGRO_EVENT_QUEUE *event_queue;
ALLEGRO_TIMER *timer;
ALLEGRO_EVENT ev;

Initialize(display, event_queue, timer);

He's passing a pointer. So the function should take a pointer or a reference, but not both. Never used both together before and honestly, I am surprised it compiled like that.

Dunno, did you say that? Do you mean the exact same binary copied from one computer to the other works on one and not the other? Or are you compiling the same source code on each one?

As has been mentioned al_init failing (somehow) seems likely - another possibility is that al_get_time is OK but the stored value (CIntroState::startTime) is being corrupted subsequently. If you get your debugger on the place where it's being set, is it always garbage?