First, close Unity and back up your entire project. I’ll take it from the tone of your post that you are not properly using source control. You should consider changing that in the future. See below.
However, AFTER you back up your project, then return to Unity.
In Unity, 100% of all your code MUST COMPILE SUCCESSFULLY before you can use any of it.
Step 1: try a reimport all.
Step 2 (if the above fails): go to the first error in the log and just investigate the error
The complete error message contains everything you need to know to fix the error yourself.
The important parts of the error message are:
- the description of the error itself (google this; you are NEVER the first one!)
- the file it occurred in (critical!)
- the line number and character position (the two numbers in parentheses)
- also possibly useful is the stack trace (all the lines of text in the lower console window)
Always start with the FIRST error in the console window, as sometimes that error causes or compounds some or all of the subsequent errors. Often the error will be immediately prior to the indicated line, so make sure to check there as well.
All of that information is in the actual error message and you must pay attention to it. Learn how to identify it instantly so you don’t have to stop your progress and fiddle around with the forum.
Remember: NOBODY here memorizes error codes. That’s not a thing. The error code is absolutely the least useful part of the error. It serves no purpose at all. Forget the error code. Put it out of your mind.
I’m sorry you’ve had this issue. Please consider using proper industrial-grade source control in order to guard and protect your hard-earned work.
Personally I use git (completely outside of Unity) because it is free and there are tons of tutorials out there to help you set it up as well as free places to host your repo (BitBucket, Github, Gitlab, etc.).
You can also push git repositories to other drives: thumb drives, USB drives, network drives, etc., effectively putting a complete copy of the repository there.
As far as configuring Unity to play nice with git, keep this in mind:
Here’s how I use git in one of my games, Jetpack Kurt:
Using fine-grained source control as you work to refine your engineering:
Share/Sharing source code between projects:
Setting up an appropriate .gitignore file for Unity3D:
Generally setting Unity up (includes above .gitignore concepts):
It is only simple economics that you must expend as much effort into backing it up as you feel the work is worth in the first place.
“Use source control or you will be really sad sooner or later.” - StarManta on the Unity3D forum boards