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I just upgraded Xcode 8.0 from beta 4 to beta 6 and I am getting this message " unable to read from device " when trying to build the app on my device. Any ideas what the problem could be?

Dan Loewenherz
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Michel Arteta
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    Restarted device helped me. – Kamleshwar Aug 16 '16 at 23:02
  • Yep, just restarting the device was enough for me, too. Glad I didn't go to the hassle of removing `iOS DeviceSupport` folder which I'm sure helps sometimes but apparently would be a waste of time and hassle at many other times. – PeterT Aug 20 '17 at 09:37
  • But when restart the device it works only once for me. Every time I try to use this I have to restart phone and this is not feasible. – Hope Sep 04 '17 at 07:31

15 Answers15

51

This is the error when the symbols are missing. Usually you get this error when your device has higher version than the Xcode such as iOS 10 vs Xcode 7.3 In this case Xcode 8 beta 6 failed to copy iOS 10 beta 6 symbols from the device.

  1. Open Devices in Xcode
  2. Select your device. It should have an unexpected error message
  3. Delete "~/Library/Developer/Xcode/iOS DeviceSupport" directory
  4. Unplug your device
  5. Restart your device
  6. Plug back your device
  7. Xcode should start copying the symbol files immediately
Tibidabo
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    This *almost* worked for me — step 4 wasn't enough, I had to restart my iOS device and quit and restart Xcode to get it to start reading the symbols, but then it did so. (Initially the Devices window showed "unable to read from device", then "unexpected" as you describe above, until I restarted Xcode.) – Nicholas Riley Aug 25 '16 at 15:21
  • @NicholasRiley probably it's more robust that way, I updated the answer. Thanks – Tibidabo Aug 26 '16 at 03:09
  • This also worked for me, after closing Xcode while unplugging and hard restarting the iOS device, and opening Xcode after having plugged in the device again. – mbo42 Aug 29 '16 at 04:16
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    Thank you for this - I was clueless! However, why delete the whole symbols folder? it took me hours to build it for all the devices I'm using. You only need to remove `rm -rf ~/Library/Developer/Xcode/iOS\ DeviceSupport/10*` – ishahak Aug 31 '16 at 12:04
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    I had the "Unable to Read Device" error. This worked for me, but had to repeat the steps and on 4, I left the device plugged in. When device restarted I got the "Unexpected Error". I restarted xcode and it began processing symbols. – johnrechd Sep 01 '16 at 16:07
  • Worked for me for the Xcode Version 8.0 GM (8A218a) and iOS 10.0.1 – Bastien Sep 12 '16 at 15:09
17

I got it to work. Try restarting your device.

If not, delete the contents of /Users/yourusername/Library/Developer/Xcode/iOS DeviceSupport, plug it into Xcode again and let it process symbol files.

diegotrevisan
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    I actually called apple and they told me to do that. Any idea regarding webkit-playsinline="webkit-playsinline" my video keeps opening fullscreen – Michel Arteta Aug 16 '16 at 02:53
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    its also worth mentioning that while a new folder is created in that directory when I plug my device in, that folder never contains anything – YichenBman Aug 16 '16 at 16:31
  • Same here. Folder is created but remains empty. Can't work :/ – rmvz3 Aug 27 '16 at 11:44
  • @rmvz3 to be honest, this has happened to me too. I still couldn't find a definitive solution. I keep trying a random sequence of deleting that path, restarting macos, restarting ios and close & open xcode-beta. It will work sometime ☹️ – diegotrevisan Aug 27 '16 at 19:59
  • @diegotrevisan In fact. My case seems to be even worst because I'm facing this problem with the official Xcode 7, not beta version :( – rmvz3 Aug 28 '16 at 16:28
  • @rmvz3 but running ios 10? – diegotrevisan Aug 28 '16 at 16:52
  • @diegotrevisan Yes. I'm running iOS10 and Sierra but I haven't had any problems until beta7. – rmvz3 Aug 28 '16 at 20:49
  • @rmvz3 Yes I'm facing it with Xcode 7 too. I meant you might have to open Xcode 8 to fix this issue (to let it process symbols). – diegotrevisan Aug 28 '16 at 21:32
  • @diegotrevisan I've already tried but it doesn't make any difference – rmvz3 Aug 28 '16 at 21:49
15

I found myself with the same issue, also my iOS > Settings > Developer: Turned out to be blank.

Solution

On iOS device go:

  1. Settings > General > Reset > Reset Network settings
  2. Device will reboot ( and you will lose wifi passwords etc )
  3. Start Xcode 8 ( beta 6 ) and plug your device in.

If this alone not work try following

  1. Unplug your device.
  2. Reboot your Mac
  3. Download Xcode 8 beta 6 and put it in applications folder.
  4. Delete content of: /Users/User/Library/Developer/Xcode/iOS DeviceSupport.
  5. Performance the steps above to Reset Network settings on iOS 10 device.
  6. When iOS device starts up plug it into your Mac, Accept it as trusted device
  7. Start Xcode 8 beta 6.

Hopefully this will work for everyone else, the list above include all the most common fixes.

Mathias Asberg
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  1. Update Xcode to Xcode 8 beta 6
  2. And Reset Network on your iPhone (Settings > General > Reset > Reset Network settings).

That worked for me.

Richard Rodriguez
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  • Cleared all my network settings including those connected to my iCloud. Keep that in mind before trying this out – Yannick Aug 22 '16 at 14:40
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I didn't need to do the Reset Network step for the phone.

WimTar
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  • +1 for `Reset your iPhone with the Home/Power button combo` This indeed triggered Xcode to process symbol files. (Note: Unplug your device while it's rebooting otherwise it mind end up in an unknown error in Xcode - Window - Device.) – DevAndArtist Aug 30 '16 at 09:31
2

Few hours back i got same issue. Following below steps fixed my issue.

  1. Restart Mac
  2. Restart iOS device
  3. Open xcode beta
  4. Open devices window from "window->Devices" menu
  5. Click on iPad and wait until "load symbols" progress indicator finishes.

It took me 10mins to load symbols, then Xcode detected device. And i had to restart twice iOS device and once Mac.

In case, if you see error after step5, hard restart iOS device (press home button and sleep button at a time and wait for apple logo to appear) and try same from step1.

My configuration: Mac(10.11.6), iPad (build version: 10.0_14A5341a), XCode 8.0 beta 6

Hope this helps :)

pastmaster
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Just restart your device

It's work for me... May be it's work for you also...

Vandit Mehta
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1

For me, changing the development target to 9 and then back to 10 worked.

Mathis Schülingkamp
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Had same issue here. Fixed it by reseting the device (Power Button + Home Button) and replacing the lightning with an original one (apparently I was using one of those replicas) .

radioaktiv
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1

Xcode 10 re-pair device fix problems for me.

  1. Open devices: select menu Xcode > Window > Devices and Simulators ⌘+⇧+2
  2. Inside window "Devices and Simulators":
    1. Select your device in left column
    2. Right click on device to open list menu
    3. Select list menu "Unpair Device"
    4. Device will show "Trust dialog" > choose trust. If dialog not shown, on device open system Settings > Developer > Clear Trusted Computers
Roman Solodyashkin
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I was facing this issue on XCode 8 Beta 4. Updating XCode to XCode 8 Beta 6 resolved the issue.

I read somewhere that "Settings->General->Reset->Reset All Settings" resolves this issue. It did not help me but I had done it anyway. Not sure if Settings need to be reset along with updating XCode.

Vinuta
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None of the above solutions worked for me. Turns out it wont download symbol files if you are using the GM for tvOS 10. I removed the provisioning profile for the GM and it worked like a charm.

Hope this was helpful to someone.

Nate4436271
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I tried the all the steps above, and reboot, restart both phone and my mac book, none of them works. I end up to download Xcode Version 8.1 (8T61a) and it works. My phone's os version is iOS 10.1 In xcode 8.1, my swift files have to have some minor syntax changes to be build.

Hannah Zhang
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my two cents: I can confirm same trivial fix for Version 9.2 (9C40b)and highSierra / OS 11.2.5 (15D60)

I got the same error, but after restarting OSX it did work.

ingconti
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-5

I had the same problem with 14A5341a. As several reboots did not lead to any improvements, I dug deeper and found that the issue appeared as soon as I started tracking my device via iCloud. As soon as I switched tracking off, everything worked as expected again.

SaSch
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