Hi guys my question is should i download and install all versions of UE4 or some of them so i can make games. I am a really newbie in this Engine but i have experience in C++ so i dont know what aspects the other version have or dont have comparing the new versions.
Download the most recent version, no need to keep more than 1 unless you need to roll back due to game-breaking bugs. You can always add/remove them later anyway. The projects are self-contained folders.
You should pick 1 version.
No, it should be fine 
Thanks for the reply. So there wont be any problems if i install just the version 4.18 and not install the others ? And there wont be any error messages like if you want to use that library you need an older version ?
The only issue you may run into is when you try to run a 3rd party plugin that has yet to be compiled for the particular engine version. Since c++ is your thing, you should be able to fix it easily, though.
Also, you can always update your project to a newer engine version and the process is automated; the engine will create a project copy before the migration. You can’t downgrade as far as I know.
The process is fully automated, I never said it always works perfectly ;p. It is true for > 99% (Windows?) users.
Is it a particular project you cannot run or you cannot launch the engine? I am not up to date on Mac issues but it cannot affect all Mac users, surely.
“Also, you can always update your project to a newer engine version and the process is automated”
Well this is not true…
UE 4.17 and above doesn’t run on my Mac for some reason… thus i can not update.
I can not launch the engine - launcher is deleting shaders folder each time.
That’s sounds pretty severe! Log a bug if you haven’t done so already. Although it does sound like an isolated issue, otherwise there’d be quite a bit of commotion if no Mac user could use 4.16+ version.
It is common - you can lookup the AnswersHub, Epic is not interested in this issue.
Some ppl said that a full format and reinstalling everybit feom scratch may resolve the issue - but I can not format… I preffer to stay on 4.16.
Click on my profile - and look at the first question - no answers what so ever.
I also mailed the support - no solution was suggested.
Regardless the Mac issue - some updates makes migrating a C++ code to a new version kind of a nightmare…
I have 90% of the project as C++ :-).