Microsoft has released build 15250 for Windows 10 Mobile Insider Preview. Learn inside about what's new in this build and how to download it.
This article is updated whenever a newer Windows 10 Mobile Insider Preview build is released.

Under Windows Insider program, Microsoft keep rolling out newer builds of Windows 10 Mobile. Now, the development team has now released Build 15250 for Windows 10 Mobile Insider Preview under Fast ring. Only following phone models may get this build:

HP Elite x3, Microsoft Lumia 550, Microsoft Lumia 640/640XL, Microsoft Lumia 650, Microsoft Lumia 950/950 XL, Alcatel IDOL 4S, Alcatel OneTouch Fierce XL, SoftBank 503LV, VAIO Phone Biz, MouseComputer MADOSMA Q601, Trinity NuAns NEO

Now lets see what steps you need to perform, in order to get Windows 10 running on your mobile:

How To Download Windows 10 Mobile Insider Preview

1. Join the Windows Insider Program using below mentioned link. If you’ve already joined the program while getting Windows 10 for desktop, then you don’t need to join it again.

Join Windows Insider Program

2. Next, download the Windows Insider app from following link:

Download Windows Insider App

3. After installing the app, open it and use your Microsoft account (on which you’ve signed for Windows Insider program). Here, you have two options. First option gives is for Insider Slow, means the build released in this ring aren’t latest one and they may have less bugs; while in case of Insider Fast you’re set to get latest and hottest build but it may have more bugs.

Download Windows 10 Technical Preview Build 10051 For Phones

From here, you can follow on-screen instructions to proceed, just like you install updates in Windows Phone. Once installation succeeded, you can have Windows 10 running on your phone.

What’s New In Windows 10 Mobile Insider Preview Build 15245

Following are highlights of this build:

  • Two-factor authentication
  • AppLocker improvements</li
  • VPN improvements

You can read about things fixed and known issues in this build and more at Windows blog:

Read more at Windows blog

Hope you enjoy this build of Windows 10 Mobile! Go here to learn how to uninstall Windows Mobile 10 and re-install Windows Phone 8.1.


  • sir can you tell me how to install this on my Lumia 520 or will it work on that? I would like to have it run on my phone soon please reply

  • Kapil Arya

    ^^ It’s yet to arrive arrived for Lumia 520, please wait :)

  • Nice info kapil I want to ask is there any specified memory req for our phones how much space we need at least??

  • Kapil Arya

    ^^ At least 8 GB.

  • hey when i open app it says check the system requirements n dnt let me to dwld new preview?!! wat shud i do pls help

  • Kapil Arya

    ^^ It’s only available for the Lumia models mentioned in the article. On other phone models, you won’t be able to proceed. It’s available for more models now. Article updated!

  • Hello I am having some trouble with my Nokia Lumia 520. I can`t personalize my start screen and lock screen; another issue is that I can`t find the Spartan browser and battery saver does not enable. please answer me. Thnkx

  • Kapil Arya

    ^^ These are known issues and Microsoft is working on them. You need to wait for next build arrival, and I hope it would fix them :)

  • Should I install it on NL 920?

  • Kapil Arya

    ^^ There are still some known issues. Do read them first via link mentioned in article, and then decide yourself should you upgrade or not :)

  • Can’t download insider app

  • Kapil Arya

    ^^ What happens when you do so?

  • My NL 1320 says no builds found. When itry the suggested alternate log in, I still run into the same problem.

  • Kapil Arya

    ^^ Have you enrolled into Insider program? If yes, try shifting to Slow ring from Fast ring and vice versa, see if it helps.

  • What about lumia 540 ?

  • Thank you Kapil! Actually my Lumia 636 had gotten stuck on build 10586 but your solution resolved!

  • Kapil Arya

    ^^ Great! One of my Lumia running 10586 crashes frequently. I believe I too upgrade it now to 14291.

  • hi please tell me kapil is nokia lumia 530 dual sim will get win 10 in feature??????

  • i can not download this build on my lumia 925 ,it says your phone is up to date .I am on build 10586

  • Kapil Arya

    ^^ Please confirm that you’ve selected Fast configuration in Windows Insider app.

  • in my lumia 630 not dowload this build , it says your phone is update

  • Kapil Arya

    ^^ Make sure you’re in Fast ring of Insider program.

  • Hey,
    i use the lumai 830 , wen i was using the 8.1 version the camera quality was superb.
    after upgrading the phone to 10 the clarity has come down. what would be the reason for that

  • Kapil Arya

    ^^ Odd! You may try updating to a newer build and see if this helps. You can also try another lens or app with different settings :)

  • can I download this build on my lumia 1020?

  • when I check for update always is: up to date (i’m in fast ring) and can’t connect to internet or server busy :(
    pls help me

  • Kapil Arya

    ^^ Make sure you’ve Windows Insider app installed. If the app doesn’t exists, your phone won’t detect latest builds.

  • Is there any way possible to hack/force an upgrade to a phone that Microsoft has dropped from the list? I am running an HTC One M8 with build 10586 Which works fine under that version and would like to upgrade to current builds.

  • Kapil Arya

    ^^ Sorry, there might be way but I don’t have any idea about it.

  • cant detect any build for nokia lumia 920
    pls help

  • Kapil Arya

    ^^ Make sure Windows Insider app exists on your phone configured to Fast ring configuration.

  • sir i have lumia 730 running mobile build 14951(fast ring)..but am not able to update latest mobile build 14965..always show device up to date.there is any solution?

  • Kapil Arya

    ^^ It might be that the build is not offered for your device. Kindly wait till next build arrives. If the problem continues, reinstall Windows Insider app and re-configure it.

  • Has this information been confirmed for the Lumia 920? Is it really possible to upgrade to the latest Fast Ring build? Thanks.

  • “phone is up to date” nokia lumia 920, windows insider app running on fast ring, please help :(

  • Kapil Arya

    ^^ Re-sync your Microsoft account. If issue persists, wait for another build release and then see if you can get that build.

  • My L920 has been stuck at build 10586 – encouraged by this site, I tried to reset my phone to defaults, reinstall Windows Insider Fast Ring, but still no updates. Maybe I’ll have to wait for another build but it’s getting quite old and I fear being left behind. For the record, I still prefer Win8.1 on my HTC 8X but losing out on some apps :(

  • Kapil Arya

    ^^ You won’t be left behind, as if you download next latest build available 😊

  • Lumia 650 not getting build 15007.

  • Kapil Arya

    ^^ Might be! Please check on next build release 😊

  • Why can I not see the windows insider build 15007 and 15014 on my Lumia 650? I´m the participiant of Windows Insider program in Fast Ring. My latest windows insider build is 14965. Can you help me what can I do?

  • I can not update my Lumia 650 to insider build 15007 or 15014 same as Arpad. My insider build is also 14965. What is solution for this problem?

  • Lumia 535 single sim. Cannot update, stuck on 14977 build. I am insider fast ring but cannot update. Is it normal?

  • Will the Insider Preview come for Lumia 520 ? I mean the latest preview 15014 ?

  • i noticed faster battery drain on Lumia 950, and finding my phone switched off all the time when battery drops lower than 20%

  • Its also downloading on nokia 1320!!!!
    With the help of modded upgrade advisor

  • after updating to build preview 15055 my lumia 1520’s display light is gone. everything is working except the display light like i can receive calls. By using microsoft recovery tool i have reinstalled windows but problem didnt rectify, only capacitive keys lights are working. what is the solution.

  • I have tried, but not working for Nokia Lumia 925

  • Hi, I have a Lumia 920 and now need windows 10 for bank apps, question, will this pre-version 15063 later be released as official w10 release , i.e. not only available for insiders?

  • Kapil Arya

    ^^ Yup, I believe. Since build 15063 is Creators Update, stable users should also get this.

  • Hi Kapil, useful article thanks. I’ve got a Lumia 925 on Win 8.1 but the Insider app advises no builds are available. (I’m registered for Insider). I don’t get a prompt about Fast or Slow rings. The link provided doesn’t mention Lumia 925.

    Any suggestions gratefully received.
    Thanks, Mike (Apr 2017)

  • Kapil Arya

    ^^ Unless you opt for Slow/Fast ring, you won’t be able to spot new builds for you. What do you see when you open the Insider app?

  • I checked today and the Nokia Lumia 920 isn’t among the phones that Windows 10 Mobile Insider Preview works on. My phone isn’t particularly old and was a pretty expensive one, so is there seriously nothing I can do to upgrade from WP 8.1 to WP 10??

  • No way of getting up to WP10 with Insider app. Didn’t even get option for slow/fast ring, just says no builds for the 925. Managed to work around using WPinternals to unlock and rename phone to 830, then Insider app offers WP10 build. Works well, seems responsive enough, battery life not as good.

  • Kapil Arya

    ^^ Thank you Mike for sharing this, hope it helps others 😊

  • Hi Kapil ..I have Lumia 1020 and have installed and enrolled to fast ring in windows insider ….havent received any update yet…its still on windows 8.1 ….Can please help me to upgrade my NL 1020 to windows 10

  • Kapil Arya

    ^^ Re-checked with Windows Insider program, Lumia 1020 is no longer listed for receiving new builds.

  • @MikeG
    How did you do to “renamed” the lumia 925 to lumia 830 with WPInternals? We have just to change the firmware? Thanks in advance.

  • @MikeG
    According to your tips I made a research and I learned how to do it.

  • Shalab, where do you get modded upgrade advisor?


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