Hello,
I just transferred my project to a different computer where i just installed Unity.
For some reason the only scene that works is my menu and i’m getting this error when opening main scene.
Failed to load ‘Assets/Scenes/GameScene.unity’ because its serialized file version is higher than what this version of Unity supports.
Help Please!
That error means that you saved the project in a higher version of Unity than the version of Unity you just tried to open it in. Are you sure the version you just installed is the latest version? I sometimes forget to clean my downloads folder and the list of 5.1.3, 5.1.0.p1, 5.2.1f1 installers can lead to a miss-click.
What is the latest version?
5.2.1 is the latest version so far.
Well that’s what i have right now so how could it have saved in a higher version?
So any ideas haha?
That is very odd. It’s possible you’ve got something corrupt going on in your project file. What I would suggest at this point is to force a re-import of all assets. Might take a while, but it could be the source of your problem.
Have you filed a bug report with Unity?
It’s also possible to open the file in notepad and drop the version number. This is a crazy hack that might cause more problems then it solves. Back up everything first!
Nope, that just brought up a ton of errors like no normals in mesh and stuff 
Bump still stuck
Hello,
I’m encountering the same issue.
all details here:
did you find a solution?
thanks
So I had this same issue with my project in 5.5.0. The issue in my case was that I had changed the Asset Serialization to “Force Text” and then had a bad merge in my git repo. I ended up with merge conflict markers in almost every file. I was able to reset to a prior commit and resolve the issue. I don’t know if it’s the issue for the OP, but it is a possible solution for some people.
Same issue when upgrading from Unity 2017 to Unity 2018 and switching from Mac to Linux at the same time. So I would recommend to either switch OS first, then upgrade the version, or vice-versa.
Since my project is versioned and the bug appeared when cloning, I still had the original version with the previous Unity on my Mac. In Unity 2017, I forced serializing to Text, then copied the file directly to the Unity 2018 project on Linux, then serialized again to Binary, and it worked.
I have the same issue in Unity 2018.3.0f2, no Unity update, just updated the “Substance in Unity” asset from Allegorithmic to the version 2.2.2.
Try do this :
In editor
Open Help → Reset packages to defaults.
It worked for me.
Make sure to back up your current project just in case 
It works with 2019.2.5 perfectly! Thanks!