Looking for some advice I have been working for a few months in an office environment and I recently was given a new role to carry out which involves input onto a shared computer. On at least two different occasions someone has been altering information I have input and I am a loss what to do. I recheck my work and have changed it back to my original input but this is getting me down. I had a confrontation yesterday with one of my colleagues who regularly undermines me and spoke to others in the office to try and get to the bottom of it. What do I do next? i was going to see my line manager with this explaining that someone has been tampering with my work and I have addressed it, I am drawing it to their attention in case it continues is this a good idea or should I wait and see if it happens again, any advice appreciated!!