Sky textures at night

I'm experiencing a rather than annoying issue, I was wondering if anyone else has seen this before and what are your suggestion.

The sky textures during the night time are not loading... If I commence a free flight and set a night time (where night sky textures need to be rendered), the game will ctd with the so hated message "A fatal error has occured". If I set any other time than night and then change it to night in-game, weirdly, it won't crash but instead, everything will be dark except for the sky textures, which will just remain the same with the time I had set before. (I had set 11:00am, the sky would be like 11:00am, but everything else, including the scenery, the clouds, the moisture and goes on, will be rendered like they are supposed to)

What do you have in mind?

It has annoyed me more than you can even imagine, because no one else seems to have ever experienced this issue before (I couldn't find any solutions by googling it.) 

It doesn't make any sense, yesterday evening it was running perfectly, and I hadn't shut down my computer since this appeared. The only thing I had done is replacing my Uires folder with the default one (A stupid thing had changed my Ui 3 months ago or so, and I replaced those with the original ones I got from a friend). I don't think that changing the UI has anything to do with this.

Things I have done so far:

Deleted fsx.cfg and let it rebuild a new one - Useless, issue is still there

Redownloaded the set of sky textures I was using (it's the Sky textures for ENB series, the most popular freeware sky textures) and replaced my old ones assuming they were somehow corrupted or something like that - Useless, issue is still there

Restarted my PC - Useless, issue is still there

Putting the old Uires folder back (which I had backed-up for a reason) - Useless, issue is still there. 

I do actually use ENB, but it's not what's causing the issue, I tried turning it off but it was useless, the issue is there. 

Any suggestions?

(English is not my native language, I hope you understand)