Guys, after that forced update this morning, I'd tried something to start the game with my mods on...
Before you start trying anything, it didn't actually work here. At the end, I've got the "Activation Key Already In Use " error message. But I have a steam version, and it's linked to R* Social... I think, if you do transfer your key code to your R* account (by R* Support Team) it may work...
This is a downgrade. So backup your original .exe and update folder to fix any future problem...
First, download the 1.0.944.2 files orignal update from (google it)
Then replace the original files by the ones you should search on google, here I only replaced my original update.rpf and GTA5.exe files. But it should be better if you reinstall the old socialmedia...
So I opened my steam with my internet conection on, double clicked on GTA V to open it.
Then appeared a steam dialog window to confirm if I want to play GTA 5 MP or SP.
I clicked OK (on Single Player) and then showed up a Windows 10 dialog to confirm that I want to open the game (administrative acc thing...) Before I accept to open the game, I turned off my internet conection and clicked on "yes" to finally open it.
After the socialmedia launcher, I turned my internet on... The game had launched, with mods, but asked me to login in an acc. I put my R* credentials, and then asked to insert my key... At this thime, that fuckin error appeared ¬¬
After I reupdated my game, the error is gone as the mods...