What can cause a special effect not to be spawned

[RobertMKD]

I have a trigger that spawns a special effect, and it worked perfectly yesterday, but today when I added other stuff to my map, the special effect does not spawn anymore, everything else in the trigger works, and I haven't changed anything in that trigger today. I've tried turning off the triggers I've added today, and then tried again, but no result.
There's also a 'destroy special effect' trigger under the spawning one, but that wasn't causing problems before, and I disabled it just to test out, so the special effect still doesn't spawns...

I would upload a trigger, but I really don't know which one should I upload, cause I haven't updated the one spawning this effect.

So what (something that I added to my other triggers) may cause a special effect not to be spawned?

 

[Veritas 117]

As strange as it may be, try restarting your computer. This happens to me occasionally where certain special effects will stop showing up. I just have to restart my comp since I basically have it on all the time.

 

[sniper_zero]

Were some skins overwritten during import perhaps?

 

[RobertMKD]

Restarted PC and it fixed the problem, but can it occur when other people play my map?

 

[Veritas 117]

I'm not sure. If it did it would probably be for the same reason. It happens pretty rarely so I wouldn't worry about it.

 

[Bribe]

Does your WarCraft 3 have the highest video quality settings?