Updated Unity - now there's mysterious compiler errors?

So I just updated to Unity 2017.3.1f1 (Windows 64bit) from Unity 3.0. Which would be super exciting (cool new updates!), but my old games from 3.0 don't work on the new version. Whenever I try to enter playmode, it says there's compiler errors that I can't seem to find the source of. They definitely weren't there before the update.

I've tried re-importing all of the assets, because that was an answer to a similar problem in an older thread, but I can't do that either. It asks me to send a bug report first, but then won't ever send the report! It just freezes.

Is anyone else having this issue? Am I missing a really obvious solution? Or is this a Unity bug?

 

Unity 3.0 to 2017 is a HUGE update. Its not at all surprising stuff broken over that stretch of difference.

But... having said that, its also very hard to know where to begin with no error information

 

you could try updating step by step, 3>4>5>5.6>2017.. and fix errors while you go,
but also note that unityscript/javascript is getting removed (boo was removed earlier), or are you using c#?

 

But you did check the Console...? -> https://docs.unity3d.com/Manual/Console.html

 

Thank you all so much for your replies! I appreciate the help so much.

Whoops! I meant 2017.3.0f3, not the original 3.0. (That'd be one hell of an update.) That was totally my bad. But I am using C#!

Yep! And the only error that came up was "All compiler errors have to be fixed before you can enter playmode! UnityEditor.SceneView:ShowCompileErrorNotification()".

I got just got the error listed above, but I did get a warning after the upgrade (not before):



The only other error info seems to be in the inspector:



Which totally wasn't there before the update. I tried replacing the component, but it thinks all of my scripts are invalid.

 

Ahhh haha. That makes more sense.

 

You should have additional errors in the console. If you don't see them it is likely you cleared them. If you close and reopen Unity it should attempt to recompile again, and display the compile errors in the console. Take a look at that before attempting to enter play mode (most people run with "clear on play" in the console, which clears all errors from the console when you attempt to enter play mode, so I'm guessing you have that set as well).