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Windows 10 build 14390 rolling out to fast ring Insiders for PC and phone

What, another build? Microsoft has just released build 14390 for Insiders in the fast ring on PC and phone which includes a number of new fixes and other improvements. Since we're at the tail-end of development, there are no new features in this build.

From today's announcement:

Improvements to PC

  • You should no longer see the error code 0x80004005 when enabling Developer Mode on the "For Developers" Settings page if your PC is using a non-EN-US language.

Known issues for PC

  • AWARENESS: A recent fix went into place for the Hyper-V firmware that will that affect the ability to boot Windows Server 2016 Tech Preview 5 VMs with Secure Boot enabled. A fix for TP5 builds has been developed however, due to release schedules, the Insider Preview build changes will be released before the TP5 fix is released. During that time, if you try to boot a new TP5 VM with Secure Boot enabled, it will fail. The workaround is to disable Secure Boot during this period.

Known issues for Mobile

  • Voice Recorder does not show up consistently as an option for Call Recording. We heard your feedback and plan to release a Voice Recorder app update via the Store soon that has the fix for this issue.
  • Wallet users are prompted for a PIN twice when using tap to pay from a locked phone. You can enter their PIN twice and tap as usual once the phone is unlocked. A fix for this will come as a Wallet app update via the Store.
  • REMINDER: We have changed the backup format for Windows 10 Mobile devices to reduce the size of the backup stored in OneDrive. As a result, if you do a backup on a device running the latest Windows 10 Mobile Insider Preview builds and move back to the released version of Windows 10 Mobile (Build 10586) and restore from your backup – your Start screen layout won't restore and remain the default Start layout. Your previous backup also gets overwritten. If you need to go back to Build 10586 temporarily, once you are on Build 10586 you should disable backup so it doesn't overwrite the good backup from Windows 10 Mobile Insider Preview builds.

My sources are telling me that this build could very well be the one that will roll-out to the public on August 2nd, meaning it's the sign-off build or "Release To Manufacturing" (RTM) build. I'm still gathering details, but it's looking increasingly likely that this is the final build. Exciting stuff indeed.

Zac Bowden
Senior Editor

Zac Bowden is a Senior Editor at Windows Central. Bringing you exclusive coverage into the world of Windows 10 on PCs, tablets, phones, and more. Also an avid collector of rare Microsoft prototype devices! Keep in touch on Twitter: @zacbowden.

285 Comments
  • Hope it fixes the battery life it was good 2 builds back but the build before this one it got worst, and the Bluetooth bug in the action center where if u turn off Bluetooth that way the phone freezes for roughly a minute....going to try to download this now
  • Hopefully this fixes WiFi issues. Still have to restart
  • Wifi connection randomly drops out and won't reconnect unless reboot? Same issue on my 950.
  • I only experienced this on my 950XL and my wife's 930 but not on my SP3... Hope it gets fixed indeed... I also think that when the build is really RTM, I'll do a hard reset on my 950XL just for the sake of it.
  • Hard resets - contrarily to what's being reported here - have not ever made any difference for me... Not with regards to performance issues, nor with regards to stability issues. Still, best of luck
  • I see hard resets as irrelevant.
    Doesn't make a difference for me.
  • it definitely solved some battery issues and flaws after updates for me in previous builds so I really do think that hard resets do solve stuff. Like format c: did solve a lot of stuff on pc :)
  • Absolutely, hard resets have often transformed my phone. I too have been having WiFi issues with my 1520 but worst my PC using a DWA182 WiFi dongle from dlink has been really bad
  • Is your shutter button still working on this build? Posted via the Windows Central App for Android
  • Yeah, but not how it should... Freezing and even some reboots when using it on locked screen...
  • Format C: only solved things for people because it was usually there actions that caused the mess in the first place.  For the Insider Program we are all at the mercy of Microsoft and bugs - we knew this when we signed up.
  • Tap to wake???????? Where it at❓❓❓❓ 950XS
  • Settings->Personalisation->Lockscreen
  • what's firmware version for your lumia 950?
  • if you were asking me, my 950 (XL) is on firmware 16236, so the one that was rolled out earlier this month (or last month??)
  • Last set of numbers... 39033
  • 35033
  • Hard Reset fixed Wifi disconnecting (showing no-internet) issue . Even I was worrying about this issue since last 3 builds.
  • A hard reset is a little extreme when we are supposed to be so close to release date.  It should not really be needed but thanks for letting us know it helped solve the issue.
  • This happens to me too on my 950XL.
  • This is still a thing? Too bad. I ordered a 950 in last November but had it in a drawer by February just for this problem. I bought a  Galaxy 7 and never looked back.
  • I have that exact issue for a few builds now (ie not introduced with this build). I thought that the wifi issues in the 950(XL) was fixed by the firmware which also re-introduced the double tap to wake??? Are you on the new firmware of last week?
    In the UK, I am (im)patiently waiting for that firmware to fixed the WiFi.
    Any news on that firmware? Had anyone in the UK received it ???
  • I have that exact issue for a few builds now (ie not introduced with this build). I thought that the wifi issues in the 950(XL) was fixed by the firmware which also re-introduced the double tap to wake??? Are you on the new firmware of last week?
    In the UK, I am (im)patiently waiting for that firmware to fixed the WiFi.
    Any news on that firmware? Had anyone in the UK received it ???
  • I have that exact issue for a few builds now (ie not introduced with this build). I thought that the wifi issues in the 950(XL) was fixed by the firmware which also re-introduced the double tap to wake??? Are you on the new firmware of last week?
    In the UK, I am (im)patiently waiting for that firmware to fixed the WiFi.
    Any news on that firmware? Had anyone in the UK received it ???
  • Try changing your location to like Germany or somewhere where they did get the firmware update
  • Try to reset using recovery tool. You will get new firmware
  • I checked yesterday and the latest firmware available from the Recovery Tool was the same firmware (i.e. Not the new update) as is already on my phone 950XL in Canada.
  • Say it again.
  • in uk with 950xl and same issue, no firmware update either , probs with glance screen where stays on when charging, do you have that issue ?
  • Yes, please fix this. Happens almost everyday I get home from work. When this happens it also stops my cellular data from working too.
  • On what phone? I don't get it on 950xl but there is a new firmware for it that fixes wifi issues.
  • Lumia 640 XL
  • The firmware update that went AWOL. Would have thought all factory unlocked phones would have gotten it first. Or at least, simply have gotten it.
  • Most ex-Nokia people were fired in last May "restructure". Consider yourself lucky if your variant ever gets the FW update.
  • My lumia 1520 have the same issue and, to top it off, the power button doesn't work anymore... I'm screw :/ Posted via the Windows Central App for Android
  • My Lumia 1520 has run the last 4-5 builds without any issue including the current build 14390.
  • This actually gave me that bug. Was 100% normal until then. Oh well I guess...
  • Battery is worst from last 2 builds. Before 2 builds it was good. Now even if i charge my phone for 8 hours while i am sleeping, it gets charged only till 85-88%
  • hmm I thought its issue with my phone...
  • Battery is very good on my 1520.
  • That Bluetooth bug.ugghh. Please report beach if it's been fixed :)
  • Yeah there are many beaches worldwide.
  • Indeed, but not that many beaches where those blue-toothed bugs live. ;-)
  • Stupid beach...
  • So...we are repeating history again! Release another half baked OS (knowingly) to the public. Wow.
  • I agree. But I think the battery issue is related to VVM. As soon as I turn it on the phone starts to heat up and the battery starts to drain up to 2-25% per hour. Without the VVM the phone stays cool with normal battery Usage. I hope they can fix this. I have reported it several times already. We'll see. Using Lumia 950xl dual sim.
  • Yea I have this same problem. Took me a couple days to figure it out. such a shame becasue its been working flawlessly for me the last couple of builds. Also my firmware update is MIA as well. Lumia 950XL DS US unlocked build 14390 and firmware 36005
  • I think 400 build will be final in anniversary update, i read it somewhere
  • Yes, I would like to see 14400 (120²) as the RTM build number.
  • Ah yes, reminds me of the good old days when 14400 baud modems were considered "fast"
  • Haha... That was ages ago :)
  • I sometimes purposely connected my 9600 baud modem at 300 to simulate that scene where a young Matthew Broderick was asked if he would like to play a game.
  • I remember loving War Games back in the day. Definitely wouldn't want to watch it now, though. That'd probably just ruin those fond memories.
  • It would divide both by 16 and by 100, like the old Vista/7/8.x days.
  • It's break more than it fixes. No point having this build
  • For PC? No. For Mobile? Those are the same issues they have existed in builds for awhile, nothing new. There are actually hundreds of small fixes and improvements not listed and considering this is very likely RTM, you'd be kind of silly to not install it. You're likely getting it anyway.
  • There's nothing broken on my build im on the slow ring right now.
  • Daniel, Is your 950XL the US Dual Sim variant and if so, do you have any issues with sending text/MMS messages or any other data related or dual sim issues? I went back to Production after the initial Dual Sim issues and I lost the ability to send text messages. I'm thinking of enrolling into the Fast Ring but I have one important game that doesn't have progress or IAP backup so I am cautious. Do you think it's a good idea to rejoin the Fast Ring now with the 950XL DS or just wait a few more weeks until RTM?
  • I would install now. I have a 950XL us dual sim and it works fine for me.
  • I have a Lumia 950 DUAL SIM and for some reason both SIM cards get stuck at 2G but if I have only 1 it can use 4G LTE. I wonder if this is a bug or not? By the way, this hasn't happened to other Dual-SIM phones I had in the past.
  • I hit reset on my phone, and didn't use a previous backup, all of my issues disappeared. I also noticed a daily increase in battery life since the last build. Much better improvements than just repeating soft resets. I think they have done a good job. (putting up my umbrella shield for this comments down votes lol
  • Daniel we have problems with this build launching apps (lumia 1520). Do you recommend a hard reset? Previous build was better. Posted via the Windows Central App for Android
  • Explain...
  • Did "Close all tabs" when attempting to close Edge with multiple tabs open break for anyone else in the last few builds? Seems like kind of an important one.
  • Since last build (updating right now to the new one), Edge would not close when having multiples tabs open, forcing me to use task manager and kill the process, is this the bug you've encountered?
  • If you manually close all the tabs it will work, but yep, that sounds like about it.
  • Yes, exactly. However it seems to be fixed in the new build
  • yep
  • Well, still not fixed in this build either. Weird.
  • Really Weird, it is fixed for me
  • I hope he started live tiles in people contact
  • Loving W10 RS, but still have dysfunctional features. Anyone have Project to/from PCs and phones running reliably? Miracast? Edge not crashing and slowing the whole OS to a crawl?
  • Want to know more about Project to PC/Mobile too...
  • To project from PC you need to open the Connect app in Windows 10 PC. Then on your phone, swipe from the top and select Connect. Your phone will search for PC and other devices connected on your network. You should be able to connect from there. Also if you have not done it, makes sure you enable project to this PC in Settings. This is under System> Projecting to this PC.
  • I've got nothing but good to say about casting via Miracast with the v2 adapter with a BT Mouse/KB. Just last night I wrote a paper while listening to Groove and taking pictures of my Leopard gecko who was keeping me company. No crashes after hours of use. I also use it to project media to my TV. (tho I have to switch to mirror screen for Netflix since it doesn't work with Continuum). My phone is casting like an absolute champion compared to my SP3 on the very same Fast Ring build.
  • Miracast is a crapshoot. It's like winning the lottery when it works. It always takes me two times to get it to connect.
  • It seems to depend on the adapter. When I connect to my TV's built in miracast, its pretty bad. My SP3 sucks at using it too. But the combo of display adapter v2 and the 950xl on fast ring is working nearly flawlessly for me.
  • My tv's built in Miracast is infuriating. OMG. I have called that tv every name in the book.
  • This exactly! Yes, I enjoyed using the MS wireless adapter, it worked great... However, I've only ONCE had project to PC work properly (950xl, 950 and 735 fail completely, rarely even seeing the (multiple) pc devices) and miracast to anything else... good luck. Utter fail with Fire TV - although, on the plus side the surface at least sees the fire TV stick, won't connect mind you, but it looks pretty in my list of available devices - one step up from mobile(s!), which don't even see it. Anyone else actually voted/reported these issues - the feedback is rather quiet/low votes in this area!!!! Sheesh!
  • Netflix works great using Edge in continuum.
  • :)
  • installing 
  • 1520, 950 XL downloading
  • How is the battery life?
  • Battery battery battery. My wife is upset about her battery life on the 950xl I hoped one of these many builds would fix that. So far not yet.. The battery saver usage says messaging and start screen are culprits..anyone else??/
  • Latest firmware or previous?
  • Many of us are still waiting for the elusive arrival of last week's HUGE firmware update that vastly improves battery life as well as the fixes the Wi-Fi issues (I suspect these two issues may be related, because right before I see the Wi-Fi issue, my phone warms up a lot and battery starts running down quickly). Anyone in the US received the new firmware yet? (I have the unlocked dual-SIM Lumia 950, so I'm stumped why we haven't seen it yet)
  • Hey, I'm one of them too.
  • I'm in Canada and no new firmware yet.
    Also my friends in Wales and Ireland haven't received it either :(
  • 'vastly improves battery life' is exaggerating it a bit. I got the firmware update (unlocked 950XL single sim) and the phone still heats up and drains battery when you use older apps that are based on 8.1/Silverlight, like WhatsApp and Skype in my case. It's a LOT better when idle however, but thats not really useful if you'd ask me. and Wi-Fi still drops from time to time (rarely though) but a quick toggle fixes it, so thats not too bad. Personally I think its the hardware. The SD810 really guzzles battery: friend of mine has a Sony Z5 Compact and that thing drains even faster with its SD810 so I've to compliment MS for optimizing the software so elegantly to work with this disaster of a CPU. Not sure what else they can do...
  • Still excited to get the FW update, but I figured as much. My idle drain is already fantastic, it's active use that's the killer. I spare my battery no expense and idle drain is about 2% per hour. Active use can go up to 20% per hour.
  • This^
    The lingering issues plaguing the 950XL in particular are probably related to the SD810. There's a good reason Samsung skipped it in the Galaxy S6. That's probably why the 950 has generally been more reliable than the 950XL. The SD810 should just be avoided where possible :-(
  • Nope, still waiting (950 XL NAM CV)
  • I'd like to know what the real story is on this firmware. SD410 issues? Found a different issue? It doesn't take this long to propagate to servers. All factory unlocked 950/XLs should have had it by now.
  • It's not a propagation issue. FW updates have to be approved individually, but Microsoft fired most ex-Nokia team in May. Who's gonna create/approve these updates? Consider yourself lucky if you ever get it.
  • Please stop with the FUD. The layoffs happened before the FW was released. If there was no one left to create and approve the updates, no one would have received the updates.
  • Hey brain. I said most, not all. And it depends by region. Learn to read.
  • The core FW was almost finished by the layoffs. But each variant has to be approved separately.
  • People are asking questions because those with factory unlocked phones are still waiting, while some locked phones have it, and that is a little unusual. But again, there has been zero indication that some 950/XL variants will get it and some will not. Therefore, FUD.
  • Previou build. 
  • From last 2 builds battery life have become worst
  • I had messaging kill my battery many builds ago. I had to stop messaging from running in the background and then restart it later and if fixed it. I had the build before this new build have my phone running hot and the Start was using the most battery. Restarting the phone did not help. I ended up powering it down and leaving it off for a while and then turningit back on, and it has been cool and fine since. Last night I still had 58% left after a long day, not heavy use, but normal use. I honnestly feel some apps or processes get stuck running in the background and for some reason, even restarting the phone does not help.  It is just a matter of figuring out how to stop that process.
  • I'm still waiting for the build in which they will enable chaseable live tiles.
  • Yes... you'll have to wait.........
  • Afaik, it is a feature that developers have to promote in their apps, like live tiles. API for the same is already available. Do correct me if i am wrong though.
    Makes me wonder though, what is stopping MS from using this feature for their own apps like news, money, sports etc.?
  • Then I guess that MS will debut the feature soon enough in their apps when Anniversary launches. Or just before that for insiders.
  • I hope they fixed Edge.  It was just bad in build 14388.
  • Yeah, Edge needs a serious fixing effort from MS. In fact with apps lacking, browser is our only resort for many tasks. Microsoft can't blame anybody else if their browser sucks :( They should target to have THE best browser across all mobile OSes. That would give us some bragging rights!
  • Where are the new live tiles ?
  • what do you mean?
  • The cheasable live tiles or something?
  • oh that is something that is already enabled on Microsoft's side. Developers just need to implement that in their apps.
  • Lol RTM? for mobile? Seriously? Typing lags on apps like WhatsApp, App crashes like Windowscentral, wifi issues, and issues here and there especially with typing and general perf. I hope they have it all.. Anyways Im happy that Im getting RTM love Microsoft for this.
  • Yeah, I still have the Wi-Fi issue all the time. I also have awful text scaling issues in Edge - makes it almost unusable. And yet, no mentions of these things AT ALL.
  • I agree with you happens on my 640 xl
  • clean install will solve those problems - Just use the Windows Device Recovery Tool to reset back to default OS and then do a clean upgrade to the current build.
  • I did eventually go with this solution, and it worked. First, I tried just an in-place hard reset (with restore from backup) because why not. It did not address scaling. Then I did a full rollback to 8.1 with the WDRT and upgraded to 10M - again, with restore because I don't have time to rebuild everything by hand. This did fix the scaling issue, and my Wi-Fi disconnect problem seems to be largely solved as well. The only real problem was that I accidentally used a restore while on a TH2 build rather than Redstone (as I meant to do), so I ran into the problem Donna S. has described with the restore point format having been changed. So I lost my startscreen and had to rebuild that. But most everything else was ultimately ok. Having to go through the WDRT process was annoying, but ultimately effective. So thanks!
  • Settings > Ease Of Access > More Options. Change text scaling to 100%. All Edge text problems went away for me. 950XL Fast Ring.
  • That's like saying that if you don't use text scaling, you don't have text scaling problems. That's not helpful; I need text scaling due to vision limitations. But see the above comment for a fix.
  • I wasn't implying that it doesn't need fixing properly, simply suggesting a workaround that I had found that worked for me until a proper fix is in place. There's no need to be quite so defensive when I was only trying to help.
  • Hail GN'R!!! What a great show.... also cool another build
  • Hell yes!!
  • Would have been nice to see improvements/fixes to mobile rather than just the PC.
  • Does it solved major issues like wifi connectivity problem and camera picture mode problem?? Does MS noticed this?
  • I feel the all-round speed has improved in last monthly update.
  • Great! Still waiting for tag editing in Groove but otherwise, I think it all looks great and everything runs so smoothly and much more fluid than in the current RTM build. I think Windows Ink is going to be a great thing for everyone who has a touch screen. Microsoft REALLY needs to advertise Windows Ink as a huge feature. What about some commercials?
  • So, nothing fixed for mobile and still no 950XL firmware for US unbranded phones lol. I still upgrade tho :P
  • i got mine days ago chief.
  • THAT'S FANTASTIC NEWS!!!! I still can't even see it in WDRT! Please confirm your device is indeed an RM-1116, a US unbranded 950XL. If so, yours is the first confirmation I've read of a US handset getting the new firmware.
  • I still can't listen to a podcast without it stopping and resetting back to where I started when the screen timeout on.my 950
  • I wanna know where my firmware update is for my unlocked Canadian 950XL DS
  • Same in the US... still waiting
  • Same in the UK... Still waiting
  • Sunstorming just a couple posts up just confirmed he got it in the US on his!
  • That's promising to see... I just checked again and no luck. I do think this is an area where Microsoft could improve with their communications.
  • Oh nice! Thanks a million for the update!! Ill check now!
  • Yes me too in Canada just waiting around.
  • i changed my 950 and 950Xl to european branded and got the new firmware.
  • What exactly did you do?
  • Shape writing accuracy is getting worse with every build.
  • I'm disappointed by this, almost RTM and still we don't have landscape start screen, still the battery life sucks and still when using a bluetooth headset the phone doesn't turn of the screen with the proximity sensor. Sad!
  • Yep.... landscape start screen was one of the most requested features... but looks like MS will need time to implement.... so we can't see it with the anniversary update.
  • Landscape start screen was never a feature slated for Redstone, so that's a touch unfair. But keep suggesting and upvoting that feedback and maybe we'll see it in the next major release. Something I was hoping for on the desktop was to see live tile folders like we have on phones. I'm really, really hoping that feature will make the next big release.
  • I just got an iPhone 6s plus for work. I dislike that GD thing, but I like the landscape mode - much better than android's.
  • Preparing to install updates 14%...
    Lumia 640xl..
  • How is your battery backup on lumia 640xl...mine was worst so i rolled back to 8.1 it used to give about 15-18 hrs on normal usage
  • One build a week should be fast ring! Phone takes 2 to 3 days to settle down before we can acually see the improvements in the build and give feedback. But with 2 builds a week, people will constantly report battery dain issues.
  • In my experience it takes up to 24 hours to settle down.
  • I found that rebooting the phone after the update ends improves battery and heat issues.
  • Hope they'll update Outlook apps soon as the only problem I have with the Anniversary Update is dead live tiles for Mail and Calendar.
  • Yeah, same here. I really thought an issue like this would be fixed by now.
  • yea and hasnt seen an update like for 2 weeks or more for these 2 apps, think they are doing something great to show us? :O