I generally recommend sticking with an actual Windows PC (doesn't have to be a server, a regular PC even running Windows Home is fine). Some NAS drives don't handle file locking properly for multi-user stuff like database access. Let's see what GPT has to say...

Running an MS Access backend on a QNAP NAS can work, but there are some risks and considerations you should be aware of:

1. **File System Compatibility**: Access is designed to run on Windows file systems like NTFS. While NAS devices often use different file systems, they usually provide compatibility with Windows via network protocols like SMB. Ensure your NAS is properly configured to handle file locking and sharing to prevent database corruption.

2. **Network Stability**: The reliability and speed of your network connection to the NAS are crucial. Any network interruption can lead to database corruption, especially with multiple simultaneous users.

3. **Backup and Recovery**: Ensure you have a robust backup strategy in place. Regular backups and a plan for quick recovery are essential to minimize downtime and data loss.

4. **Concurrency and Performance**: While your setup is working well now with 10 users, performance may degrade as the number of users or the complexity of queries increases. Monitor performance and be prepared to adjust configurations or scale resources if needed.

5. **Data Integrity**: Be aware that Access databases can be prone to corruption in non-Windows environments, especially if there are network issues or improper shutdowns. Regular compact and repair operations can help maintain database integrity.

6. **Support and Updates**: Ensure your NAS firmware and any software used to interface with the NAS are kept up to date. This can help address security vulnerabilities and improve compatibility.

In summary, while your current setup is functioning well, it's important to continuously monitor performance and data integrity, maintain a reliable network, and implement regular backups. Being proactive about these aspects will help mitigate risks and ensure long-term stability.

Pretty much what I said. Be careful with concurrent users. If you've only got a couple you should be OK.... The more users, the more the risk.

Richard, I very much appreciate this analysis.  Frequent backups and a UPS should help.

Essentially, Microsoft Access is a file-based database system, so as long as the individual workstations handle file locking properly, then you shouldn't have any problems. Access is not a database server like SQL Server, so the individual workstations are responsible for doing all the file I/O work and locking the records they're on. As long as your NAS can handle that, then you shouldn't have a problem.