If you're getting ERROR 260 when you try to launch the game, your launcher cache is most likely corrupted.
1) Close your Launcher
2) Go to: C:UsersYOURUSERNAMEAppDataLocalBattlestate GamesBsgLauncher
3) Delete both the CefCache and the Logs folder (you probably only have to delete CefCache, I just deleted both), make a backup if you're unsure.
You can also get there easily by typing %temp% in your file explorer and then clicking on "Local" in the location bar.
Start the Launcher (You'll have to login again)
This fixed it instantly for me.
Cleaning Temp folder from within the launcher DOES NOT WORK, it's not the same folder so don't waste your time trying that.
//Edit: Unfortunately doesn't seem to work for everyone, it did work for me and a couple others on discord, so it's worth a try, make sure you're in the right place, LOCAL not ROAMING.
Source: https://www.reddit.com/r/EscapefromTarkov/comments/fmiq0q/how_to_fix_error_260_instructions_inside/