1. Take Security Measures
  2. Secure Physical Access
  3. Ensure office cleaning is carried out during working hours or under permanent surveillance

Ensure office cleaning is carried out during working hours or under permanent surveillance

A possible solution is to encrypt the workstations and to make it compulsory for them to be switched off outside office hours.

Always lock workstations (CTRL + ALT + DEL or Windows Key + L) when absent. Also secure laptops with a laptop lock and a key to prevent theft.