Concurrency is the ability of a computer system to perform multiple tasks simultaneously. Beginner programmers may face several challenges while learning about concurrency. Here are 10 common challenges they may encounter:

1. Understanding the concept: The concept of concurrency can be difficult for beginners to grasp, especially if they are new to programming.
2. Debugging: Debugging concurrent programs can be challenging, as it is often difficult to identify the source of a bug or error.
3. Race conditions: Race conditions occur when two or more threads access shared resources at the same time, leading to unpredictable results. Beginners may struggle to detect and avoid race conditions.
4. Deadlocks: Deadlocks occur when two or more threads are waiting for each other to release resources they are holding, resulting in a deadlock. Beginners may struggle to identify and resolve deadlocks.
5. Synchronization: Synchronization is essential to ensure that threads access shared resources in a controlled manner. Beginners may find it difficult to implement synchronization correctly.
6. Performance issues: Concurrent programs can suffer from performance issues due to excessive synchronization or contention for shared resources.
7. Scalability: Scaling concurrent programs to take advantage of multiple processor cores can be challenging for beginners.
8. Testing: Testing concurrent programs can be difficult, as it is hard to reproduce and isolate concurrency-related bugs.
9. Choosing the right concurrency model: Beginners may find it difficult to choose the right concurrency model for their application, as there are several models available.
10. Complexity: Concurrency can add significant complexity to a program, making it harder to understand, debug, and maintain.

Overall, while learning about concurrency, beginners may encounter several challenges. However, with practice, they can overcome these challenges and become proficient in writing concurrent programs.