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?
Xcode8.0 Beta 6 - unable to read from device
21.2k Views Asked by Michel Arteta AtThere are 15 best solutions below

Few hours back i got same issue. Following below steps fixed my issue.
- Restart Mac
- Restart iOS device
- Open xcode beta
- Open devices window from "window->Devices" menu
- 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 :)

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.

I found myself with the same issue, also my iOS > Settings > Developer: Turned out to be blank.
Solution
On iOS device go:
- Settings > General > Reset > Reset Network settings
- Device will reboot ( and you will lose wifi passwords etc )
- Start Xcode 8 ( beta 6 ) and plug your device in.
If this alone not work try following
- Unplug your device.
- Reboot your Mac
- Download Xcode 8 beta 6 and put it in applications folder.
- Delete content of: /Users/User/Library/Developer/Xcode/iOS DeviceSupport.
- Performance the steps above to Reset Network settings on iOS 10 device.
- When iOS device starts up plug it into your Mac, Accept it as trusted device
- Start Xcode 8 beta 6.
Hopefully this will work for everyone else, the list above include all the most common fixes.

- Update Xcode to Xcode 8 beta 6
- And Reset Network on your iPhone (Settings > General > Reset > Reset Network settings).
That worked for me.

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.
- Open Devices in Xcode
- Select your device. It should have an unexpected error message
- Delete "~/Library/Developer/Xcode/iOS DeviceSupport" directory
- Unplug your device
- Restart your device
- Plug back your device
- Xcode should start copying the symbol files immediately

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) .

- Update Xcode to Xcode 8 beta 6 (https://developer.apple.com/download/)
- Reset your iPhone with the Home/Power button combo
I didn't need to do the Reset Network step for the phone.

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.

Xcode 10 re-pair device fix problems for me.
- Open devices: select menu Xcode > Window > Devices and Simulators ⌘+⇧+2
- Inside window "Devices and Simulators":
- Select your device in left column
- Right click on device to open list menu
- Select list menu "Unpair Device"
- Device will show "Trust dialog" > choose trust. If dialog not shown, on device open system Settings > Developer > Clear Trusted Computers

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.
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.