Leakage of sensitive data stored on lost or stolen portable devices has been an open problem in the data security community. Clumsiness of existing solutions hinders them from being deployed. We propose a user-friendly location-free encryption system for mobile users (UFLE) to improve the solution Mobile User Location-specific Encryption (MULE) from Studer and Perrig on both the security and usability. In particular, we solve the problem of (i) enhancing the convenience and security of MULE, (ii) accessing sensitive data in untrusted locations, and (iii) protecting data on stolen or lost USB flash drive, which were not addressed in their solution. Moreover, UFLE does not require any special hardware except a mobile phone and a Bluetooth adapter, which are readily available nowadays. This significantly improves the practicability of the proposed system in contexts such as business companies, government offices, hospitals, and banks. Evaluation of our system shows that it is both faster and more stable than MULE. Copyright © 2012 John Wiley & Sons, Ltd.