How to reproduce:
1. Open Unity
2. Select Learn
3. Choose Basic Tutorials
4. Download and start one of four tutorials
5. When editor opens, close it
6. If you opened Unity 2017.2.x version, now open 2017.3.x
7. Select Learn
8. Chose Basic Tutorials
9. Start the same tutorial that you downloaded before
10. Wait until it loads and then Unity crashes

Regression first introduced in: 2017.3.0a4
Reproducible with: Downloaded on 2017.2.0b2-2017.2.0f3 Started with 2017.3.0a4-2017.3.0b6 and 2018.1.0a1
Not reproducible with: Downloaded on 2017.2.0.0b2-2017.2.0f3 Started with 2017.3.0a3

Note:
This issue doesn't occur when Tutorials are downloaded with 2017.3.x versions and started with 2017.2.x