2026 Master Guide: How to unlock the Vehicle Unit (VU), manage previous company locks, and ensure data custody compliance.
The company lock is a logical security feature of the digital tachograph designed to protect the privacy of activity data. When a transport company acquires a vehicle, it must "lock" it using its own company card. This action establishes a period of ownership in the tachograph's memory, ensuring that only that specific company can download the .DDD files corresponding to its management period.
In 2026, with stricter data protection regulations and sector competition, encountering a blocked download is a common issue, especially with second-hand vehicles. If the previous owner did not perform a "lock-out," the new owner may find it technically impossible to access the data, leading to a serious breach of documentary custody obligations.
The clearest symptom is the message "Card not valid for this period" or simply a reading error when trying to download VU data. The tachograph protects the previous owner's data, preventing you from viewing their commercial activity.
If you have renewed your company card and the tachograph does not recognize it as the "master key," it could be due to a card conflict caused by expired digital certificates in the vehicle unit.
To avoid fines from the Transport Inspectorate, you must follow this protocol every time a vehicle enters your fleet:
Insert your company card into any of the slots (preferably Slot 1). The tachograph will identify it and, if it is the first time, will ask if you wish to perform a company lock.
If the vehicle is new to you, the system will notify you that a previous lock exists. By accepting the new lock (lock-in), the tachograph generates a "timestamp." From that second forward, all generated data legally belongs to you and can be downloaded without restrictions.
Being unable to download data due to a technical locking issue is not a valid excuse before the Administration. According to the 2026 sanctions scale, the lack of vehicle unit data is considered a Very Serious infringement.
Managing company locks is the cornerstone of a solid legal defense. At TachoTools, we help companies verify that their locks are correctly implemented by analyzing the structure of .DDD files. A simple error in lock configuration can leave your company exposed to massive fines for lack of data during an official audit.
Upload your file to check if the locking period is correct and legal.
Next step
At TachoTools, we analyze why your tachograph is blocked and guide you through regaining compliance for your files.