I am not a big data user on my phone. I am usually connected via WiFi at home and work, where I spend most of my day. I don't stream music or video. Generally I use about 1/2 GB per month when not traveling. So I was shocked when my Android Phone warned me when I exceeded 2 GB this month. I'm up to 2.4 GB so far. It's not a crazy amount of data, but far more than I usually use.
So, I looked into the details to find the culprit. It was not even close. OneDrive (Microsoft's cloud documents app) had used 1.9 GB of data. Even worse, I don't think I even opened the app all month. I tested OneDrive a couple of months ago, and uploaded some test data to the cloud. But since then I have not used it. I much prefer Google Drive, which is where I do all my work (less than 0.1 GB used in Google Drive.
Therefore, OneDrive is doing a heck of a lot in the background. I cannot imagine what it is doing with all that data. Either it is uploading and downloading the few measly MB of data I have saved on it all day every day, or it is going through my phone and doing heaven knows what. I also have it set not to upload pictures except when connected to WiFi and plugged in. That did not seem to help.
Given that OneDrive is of minimal use to me, and the fact that it is sucking down all my data behind my back, I am uninstalling it now.
I am disappointed that Microsoft still cannot get its act together and design quality software that works efficiently. There was a time when Microsoft cared about such things, but that was long ago, in another millennium. Changing CEOs has not seemed to help matters. Microsoft has a reputation for fat, overloaded bloatware. The new CEO Satya Nadella showed some promise to get back to this. But my experience with OneDrive speaks volumes to me.
Therefore, farewell Microsoft. You briefly found your way back onto my phone with the hope that you could be useful to me again. You failed miserably and I have banished you once again.