The Case of High Data Usage on Windows 10 Mobile

The Problem

Data Usage (1)I have a 1GB/month data plan and shortly before the month reset in mid-January, the data usage reported in Settings was abnormally high. It wasn’t that any of the apps had used more data, but rather the crux was operating system itself: More than 98% of my data plan had been consumed by System. No details were given as to what exactly System was using all that data for.

The Diagnosis

I had been traveling abroad to Bern, Switzerland in early January, and in the process meddled with a few settings, so my phone would less data during the time.

Checking Settings

My first instinct was that I must have done something wrong when I reset everything upon returning home:

  • Camera upload settings in the OneDrive app
  • App update settings in the Store app
  • System update settings under Advanced Settings
  • Backup and Find My Phone under Settings –> Update & Security

Unfortunately, everything looked  fine.

Then I tweeted @LumiaHelp, Microsoft’s Lumia/Windows Mobile support account. During our lengthy exchange, they pointed me to a few more things to reduce data usage I should check.

Unfortunately, they all looked fine too.

Other Ideas

Data Usage (2)I once had an issue with my Wi-fi, such that even though I was home and should have been in range, I watched a movie on Netflix over the cellular network by accident. Hence I looked at a detailed log of when data was used, but it looked like those were times I was away from home, so it had to be something different.

As the month had just reset and I was back to 1 GB of data, I looked at data usage every hour every hour. Within a day, System had already used 123 MB. Overall it looked like System was using about 10MB/hour while the other apps were inconspicuous having used about 7MB in total.

I would not get very far with data being consumed at this rate. @LumiaHelp had the rather unhelpful suggestion that I could easily turn off my data connection from Action Center. I did that to save on data in the short run, but obviously this was not going to be a long-term solution. I was convinced now that it had to be a bug in Windows 10 Mobile. But @LumiaHelp wasn’t being helpful anymore.

The Solution

Turn off Message History SyncAt about the same time Paul Thurrott tweeted about the issue and a reply to his tweet pointed my in the right direction: Turning off message sync under Settings in the Messaging app.

Without message sync, my cellular data usage immediately went back to normal. I also found this discussion on Reddit about the issue. According to user JennMSFT it is on the Windows 10 Mobile team’s radar. So I’m holding out for a fix in a future operating system update. I’m not really sure what history sync was even working before. I haven’t seen my text messages show up in the Messaging app on my Surface running Windows 10.


Trip to Bern, Switzerland

I have a list of European capitals that I want to visit. So when I had a few days off work over New Year’s, I saw an opportunity to cross one off the list.

My destination of choice was Bern, Switzerland, since it has a convenient direct train connection to my home town and promised to be mostly free of New Year’s celebrations.

Granted, this time of year is not ideal for visiting, but at least it was as quiet as I had hoped. The weather wasn’t great, but I did get to walk around the charming old city and do some hiking in the nearby forests.


Altstadt bei Nacht

One thing I found quite surprising was the parliament building Bundeshaus. I had expected something a lot more modest, but instead the Swiss went all out with a very representative building, famously made almost entirely with materials and by artists and workmen from all over Switzerland.


And even the one day that it was raining almost non-stop wasn’t a complete loss: I found that Netflix offers quite a few shows in Switzerland that aren’t (yet?) available here in Germany, so I got to watch a few of those.