Common causes of compilation errors
Upgrade a project from an older version of Unity to a newer version. Open a project in a different version of Unity from the one it was created in. See in Glossary, or an incorrect version of a package. Open a project which has errors in your own scripts.
Compiler errors are generated by a script that has erroneous code. By double clicking on the error message or opening the script directly, you must open the script in a text editor and fix the error described.
If any of the scripts in your Unity project have errors that do not allow Unity to compile the scripts, this error will be displayed.
Importing assets that contain scripts can result in the above error. Check the compatible Unity versions for the asset. The code may be outdated and no longerĀ
When you create a script in Unity and click play to test the script is working, you may receive some bright red error text in the collapsed version of the Console located in the bottom left corner of the Unity Editor: The red text is the type of compiler error in your script.