It looks as though Microsoft hasn’t quite worked out all of the kinks when it comes to installing (or uninstalling) Windows 10 on smartphones that are supposedly supported. Earlier this month, Lumia 520, 525, and 526 owners ran into difficulties when attempting to uninstall Windows 10 Technical Preview Build 10051 to revert back to Windows 8.1.
Microsoft made some tweaks to the Windows Phone Recovery Tool (WPRT) to alleviate the issue and proceeded to release Windows 10 Technical Preview Build 10052. Everything should be all hunky-dory now for supported Lumia smartphones, right? Well, you’d be wrong — but this is to be expected with software that is still in beta.
This time around, it’s Lumia 640 users that are experiencing problems with Build 10052. And the problem appears to be similar the issues that we saw with the Lumia 520 and its ilk. In a posting on the Microsoft Community forum, a moderator, Jason[MS], posted the following bit of bad news:
If your 640 handset is on Windows Phone 8.1 and has an OS version greater than 8.10.15116.125, you will not be able to upgrade to Windows 10 Technical Preview currently. To check the current OS version of your device: Settings > About > (More Info)
I know this news is disappointing. This is a temporary, not permanent, situation. Without going into great technical detail, I will summarize and say that if you are on a build greater than the one noted above and update to Windows 10 Technical Preview, your device would not be able to recover back to Windows Phone 8.1 if you were to encounter any device troubles or decide the Preview wasn't to your liking.
So for now, Lumia 640 are strongly encouraged to back away from installing Windows 10 Build 10052 until Microsoft can resolve the issue. “This is not a situation we want to put users in,” Jason[MS], conceded. “Having the ability to recover or roll-back should you choose is important.”
Microsoft came up with a quick fix for Lumia 520/525/526, so hopefully the company will quickly come to the rescue of Lumia 640 users as well that want to try out the latest build of Windows 10.