Microsoft is telling Windows 10 mobile users to shut off automatic updates, because a bug is demolishing people's data allowances.
The antics of the Windows 10 Mobile Insider Preview edition has lit up forums like Reddit and Windows Central, because it assumes users believe “back up everything to the cloud on whatever network is available - including cellular” should be everybody's default setting.
As a result, users that have installed the preview on Lumia devices are watching their data allowances get gobbled by Windows 10 sending backups of their SMSs, MMSs and apps over the mobile connection.
Microsoft Redditor "Jenmsft" told Reddit users should “turn off app backup and messaging sync” to save their data.
The issue seems to have been present since an October build of the operating system: this post at Windows Central dates to October 2015, and reports the same issue on Build 10572.
The same thing was reported at Windows Central for a December build.
The most detailed description The Register has found so far was from 17 days ago on the Windowsphone sub-Reddit, here.
“It looks like message syncing is getting funnelled into 'System' when data is being used,” user hulkulesenstein. “Furthermore it seems that this data is ONLY being synced while on mobile as I had wifi on last night after reset and System usage was only 3MB. And finally, even though I had it set to 30 day sync my phone was syncing SMS and MMS from YEARS ago to my phone just destroying my data”.
Microsoft really should be getting this right as apps like its own OneDrive offer the chance to do cloud backups only when Wi-Fi connections are present, precisely because users' mobile data allowances are typically anaemic compared to home and business connections. ®