How to Fix Unity “All Compiler Errors Need to Be Fixed” and Exit Without Saving

If you’ve ever tested demo scenes from the Unity Asset Store, you’ve likely encountered a situation where importing an asset messes up your project. When this happens, Unity won’t let you enter Play Mode until you fix all compiler errors. The message you see:

“All compiler errors need to be fixed before you can enter playmode!”

At this point, you might want to undo the import and return to the last working state. However, Unity doesn’t have a built-in “undo” feature for asset imports. Even exiting without saving doesn’t work, as Unity often loads the broken state when you reopen the project.

So, how can you test assets without risking your entire project? Let’s explore some efficient workarounds to avoid redundant steps.

1. Use Version Control (Recommended Approach)

Using Git or Unity Plastic SCM can track changes before importing assets. This allows you to revert back if an asset breaks the project.

Steps for Git Users

• Open a command prompt (Windows) or terminal (Mac/Linux) in your Unity project folder.
• Initialize Git (if you haven’t already):

git init
git add .
git commit -m "Pre-import backup"

• Now, import the asset.
• If the project breaks, use:

git reset --hard HEAD

• Restart Unity—your project will be back to its last saved state.

Steps for Unity Plastic SCM Users

1. Enable Version Control in Unity under Edit → Project Settings → Version Control.
2. Before testing an asset, make a snapshot.
3. If things go wrong, simply revert to the previous snapshot.

2. Manually Backup the Project Folder

If you don’t want to use version control, you can manually create a backup copy of your project before importing assets.

How to Back Up Your Unity Project:

1. Close Unity.
2. Go to your Unity Projects folder.
3. Copy the entire project folder and rename it (e.g., MyProject_Backup).
4. If the imported asset causes issues, delete the broken project and restore the backup.

This method is simple but requires extra disk space.

3. Delete Unity’s Library Folder to Force a Reset

Unity often caches changes in the Library folder, which might be why exiting without saving doesn’t restore your last state.

Steps to Reset the Project by Deleting the Library Folder

1. Close Unity.
2. Navigate to your Unity project folder.
3. Delete the Library folder.
4. Restart Unity—this will force a rebuild and might fix the issue.

Note: This method can take some time, as Unity needs to regenerate files.

4. Test Assets in a Separate Unity Project

Instead of importing assets into your main project, create a separate test project dedicated to asset testing.

Steps:

1. Open Unity Hub → Create a New Project (name it something like AssetTestProject).
2. Import assets into this test project first.
3. If the asset works well, export only the required parts as a .unitypackage.
4. Import the .unitypackage into your main project.

This way, your main project remains safe from unwanted changes.

5. Use Unity Collaborate (Cloud Version Control)

If you’re using Unity Collaborate (part of Unity Teams), it allows you to save a cloud backup and revert changes when needed.

How to Use Unity Collaborate:

1. Go to Window → Unity Services and enable Collaborate.
2. Click Publish to save your current project state.
3. If an imported asset breaks your project, simply restore a previous version.

This is an easy and built-in option for Unity users with Unity Teams.

6. Fix Compiler Errors Instead of Resetting the Project

If you don’t want to delete your project, try fixing the compiler errors instead.

Steps to Fix Compiler Errors:

1. Open the Console Window (Window → General → Console) and check error messages.
2. If an imported script is causing issues, try:
   • Deleting the script from the Assets folder.
   • Commenting out problematic code.
   • Removing conflicting packages in Edit → Project Settings → Package Manager.

This method works if only one or two scripts are causing problems.

Final Recommendation: The Best Workflow for Testing Unity Assets

To avoid project corruption, use the following workflow:

• Step 1: Create a backup (Git, manual, or Unity Collaborate) before importing assets.
• Step 2: Test assets in a separate Unity project whenever possible.
• Step 3: If the project breaks, revert using Git or restore the backup.
• Step 4: If you forgot to back up, try deleting the Library folder or fixing compiler errors manually.

Conclusion

Unity’s compiler errors can be frustrating, especially when experimenting with Asset Store imports. However, by using version control, backups, or separate test projects, you can avoid losing progress and save time.

Did this guide help? Let us know your preferred method in the comments!