Why aren't simulators showing in the Xcode 6.3

I cannot seem to build for a simulator in Xcode 6.3.1

The scheme selector only lists iOS Device or my plugged in device as seen below:

xcodebuild -showsdks lists it:

OS X SDKs:
    OS X 10.9                       -sdk macosx10.9
    OS X 10.10                      -sdk macosx10.10

iOS SDKs:
    iOS 8.3                         -sdk iphoneos8.3

iOS Simulator SDKs:
    Simulator - iOS 8.3             -sdk iphonesimulator8.3

It appears to be in the correct location in the app bundle.

I also can't build for i386 and x86_64 using xcodebuild

The output from xcrun simctl list is as follows:

== Device Types ==
iPhone 4s (com.apple.CoreSimulator.SimDeviceType.iPhone-4s)
iPhone 5 (com.apple.CoreSimulator.SimDeviceType.iPhone-5)
iPhone 5s (com.apple.CoreSimulator.SimDeviceType.iPhone-5s)
iPhone 6 Plus (com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus)
iPhone 6 (com.apple.CoreSimulator.SimDeviceType.iPhone-6)
iPad 2 (com.apple.CoreSimulator.SimDeviceType.iPad-2)
iPad Retina (com.apple.CoreSimulator.SimDeviceType.iPad-Retina)
iPad Air (com.apple.CoreSimulator.SimDeviceType.iPad-Air)
Resizable iPhone (com.apple.CoreSimulator.SimDeviceType.Resizable-iPhone)
Resizable iPad (com.apple.CoreSimulator.SimDeviceType.Resizable-iPad)
== Runtimes ==
iOS 8.3 (8.3 - 12F69) (com.apple.CoreSimulator.SimRuntime.iOS-8-3)
== Devices ==
-- iOS 8.3 --
-- Unavailable: com.apple.CoreSimulator.SimRuntime.iOS-7-0 --
    iPhone 4s (12AE8BFB-0540-4BC0-AB56-459304D05E2A) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5 (1DA1B3F7-48D5-484E-95F9-CF913DF85B63) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5s (A1B771C1-834F-4E05-A04F-7E9A3505D46E) (Shutdown) (unavailable, runtime profile not found)
    iPad 2 (B4E0D353-F942-459E-995C-49183245ECAA) (Shutdown) (unavailable, runtime profile not found)
    iPad Retina (6D7E2406-9C7A-40DC-B217-D0B0FE3CEAEE) (Shutdown) (unavailable, runtime profile not found)
    iPad Air (B03E0F6B-3110-40CD-98F8-190726489B56) (Shutdown) (unavailable, runtime profile not found)
-- Unavailable: com.apple.CoreSimulator.SimRuntime.iOS-7-1 --
    iPhone 4s (0DB72F1A-A5D0-4556-A49E-B96853B439F2) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5 (22BFA786-5AE0-4ABA-9062-DE358CFB0D6C) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5s (2F59F49A-AAF8-40C3-BB60-30C729A979F3) (Shutdown) (unavailable, runtime profile not found)
    iPad 2 (DCAB9F55-9D6B-473E-9433-D2D48203B4DB) (Shutdown) (unavailable, runtime profile not found)
    iPad Retina (8F74FE32-DE70-4C4B-9D81-21856C9866DA) (Shutdown) (unavailable, runtime profile not found)
    iPad Air (650CF55A-2BD7-425A-8939-CADEADB7068A) (Shutdown) (unavailable, runtime profile not found)
-- Unavailable: com.apple.CoreSimulator.SimRuntime.iOS-8-0 --
    iPhone 4s (73837B7E-8E11-4616-AE13-23F60728FBF3) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5 (2E3268E4-2E35-44BC-AF3D-F32306D44F13) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5s (C8ECDF4C-DE68-4A73-9ECA-546E85A3DA80) (Shutdown) (unavailable, runtime profile not found)
    iPhone 6 Plus (BB59A82C-BC47-4B51-A3B8-F0123394292A) (Shutdown) (unavailable, runtime profile not found)
    iPhone 6 (8E37DC02-393F-4695-980C-8679A5D56E46) (Shutdown) (unavailable, runtime profile not found)
    iPad 2 (7503B827-8037-4465-AE57-02AFB54CE204) (Shutdown) (unavailable, runtime profile not found)
    iPad Retina (6629BF4B-6CBA-43A3-8EA2-93272933D086) (Shutdown) (unavailable, runtime profile not found)
    iPad Air (61747A6D-BDDC-4906-87DA-CB8FD0678A93) (Shutdown) (unavailable, runtime profile not found)
    Resizable iPhone (CFD3BE4E-1205-4EF6-BF4B-F1CFE5490040) (Shutdown) (unavailable, runtime profile not found)
    Resizable iPad (89A63BCF-A654-44BE-8362-5544F5FA1CAF) (Shutdown) (unavailable, runtime profile not found)
-- Unavailable: com.apple.CoreSimulator.SimRuntime.iOS-8-1 --
    iPhone 4s (FE578030-E512-4643-9F28-FCDCCD74279F) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5 (9C328DC5-2E4F-47AB-ABBA-1C881DE48795) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5s (8D91EB18-594B-4288-BBF4-BF2655308706) (Shutdown) (unavailable, runtime profile not found)
    iPhone 6 Plus (70F1B2D6-966D-49F0-B6CE-BCF995F425CB) (Shutdown) (unavailable, runtime profile not found)
    iPhone 6 (53510FD4-EEE0-487E-B20E-F9F8AC65BA57) (Shutdown) (unavailable, runtime profile not found)
    iPad 2 (3B316D24-6497-45C1-BE0D-690FA831D6A3) (Shutdown) (unavailable, runtime profile not found)
    iPad Retina (55ED45DA-3ACB-479C-9FF9-F0905B47A497) (Shutdown) (unavailable, runtime profile not found)
    iPad Air (52AE24F1-92AE-4198-A196-32A4691903D8) (Shutdown) (unavailable, runtime profile not found)
    Resizable iPhone (1E16E2F4-BC24-4F3D-AB1F-C07A6FA52E6F) (Shutdown) (unavailable, runtime profile not found)
    Resizable iPad (95254D91-345C-446E-8CC7-72382C0AB8AD) (Shutdown) (unavailable, runtime profile not found)
-- Unavailable: com.apple.CoreSimulator.SimRuntime.iOS-8-2 --
    iPhone 4s (4370C11F-7486-4E16-AD62-04BC6ECF23CC) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5 (1635F9A2-5CD6-4669-B69B-493EDA2736BF) (Shutdown) (unavailable, runtime profile not found)
    iPhone 5s (AD9B417C-BB60-4A94-A080-4E9A00577762) (Shutdown) (unavailable, runtime profile not found)
    iPhone 6 Plus (A1575F64-44E1-4999-985E-88B890354A36) (Shutdown) (unavailable, runtime profile not found)
    iPhone 6 (44F34FBC-924E-4226-AF8B-C9C76C618457) (Shutdown) (unavailable, runtime profile not found)
    iPad 2 (180A9123-2F6C-423D-A124-CAAEEC8661D5) (Shutdown) (unavailable, runtime profile not found)
    iPad Retina (0BBD9657-498C-4823-BA0B-4A5EA7305224) (Shutdown) (unavailable, runtime profile not found)
    iPad Air (57E7ED1B-89BB-4C0E-A167-7D6FDD97E838) (Shutdown) (unavailable, runtime profile not found)
    Resizable iPhone (C56D2AC5-9F7A-4C8B-BCED-997A32D7342B) (Shutdown) (unavailable, runtime profile not found)
    Resizable iPad (27E051F5-F718-4BDC-99AA-F8C66B66505E) (Shutdown) (unavailable, runtime profile not found)

The applicable portion of the core simulator log is:

May  5 14:31:07 Fangorn-Farm-3.local CoreSimulatorService[6031] <Notice>: com.apple.CoreSimulator.CoreSimulatorService 117.15~1 starting.
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/14E7FDD6-751B-4A81-9CAF-B7F8359C553F/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/57028519-A154-4768-87D7-589111236C12/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/726D5E5A-A5C2-4EEA-B18E-C5174AE7EFD4/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/79272BA7-45B9-47C4-A74E-91A9A1C02141/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/A4526FAE-721D-488F-B9F6-D0D6A31EE579/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/ACE62A2C-E3E0-408F-A198-983D244107E7/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/DB987632-15E5-4CB4-B20C-1FF8FF4606C6/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/E1F83FA1-F630-4CDB-9E2D-8792797BEA5E/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/E45166AD-7ED3-4001-B01C-3B8F8497ECEA/device.plist
May  5 14:31:08 Fangorn-Farm-3.local CoreSimulatorService[6031] <Error>: Unable to load device.plist: /Users/montegoulding/Library/Developer/CoreSimulator/Devices/FE7A9682-FF80-4F7E-9817-A1B2CFDA0328/device.plist
May  5 14:31:08 Fangorn-Farm-3.local com.apple.dt.Xcode[754] <Warning>: CoreSimulatorService connection interrupted.  Resubscribing to notifications.

The content of ~/Library/Developer/CoreSimulator/Devices/.default_created.plist is:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>com.apple.CoreSimulator.SimRuntime.iOS-7-0</key>
    <dict>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-2</key>
        <string>B4E0D353-F942-459E-995C-49183245ECAA</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Air</key>
        <string>B03E0F6B-3110-40CD-98F8-190726489B56</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Retina</key>
        <string>6D7E2406-9C7A-40DC-B217-D0B0FE3CEAEE</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-4s</key>
        <string>12AE8BFB-0540-4BC0-AB56-459304D05E2A</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5</key>
        <string>1DA1B3F7-48D5-484E-95F9-CF913DF85B63</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5s</key>
        <string>A1B771C1-834F-4E05-A04F-7E9A3505D46E</string>
    </dict>
    <key>com.apple.CoreSimulator.SimRuntime.iOS-7-1</key>
    <dict>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-2</key>
        <string>DCAB9F55-9D6B-473E-9433-D2D48203B4DB</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Air</key>
        <string>650CF55A-2BD7-425A-8939-CADEADB7068A</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Retina</key>
        <string>8F74FE32-DE70-4C4B-9D81-21856C9866DA</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-4s</key>
        <string>0DB72F1A-A5D0-4556-A49E-B96853B439F2</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5</key>
        <string>22BFA786-5AE0-4ABA-9062-DE358CFB0D6C</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5s</key>
        <string>2F59F49A-AAF8-40C3-BB60-30C729A979F3</string>
    </dict>
    <key>com.apple.CoreSimulator.SimRuntime.iOS-8-0</key>
    <dict>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPad</key>
        <string>89A63BCF-A654-44BE-8362-5544F5FA1CAF</string>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPhone</key>
        <string>CFD3BE4E-1205-4EF6-BF4B-F1CFE5490040</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-2</key>
        <string>7503B827-8037-4465-AE57-02AFB54CE204</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Air</key>
        <string>61747A6D-BDDC-4906-87DA-CB8FD0678A93</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Retina</key>
        <string>6629BF4B-6CBA-43A3-8EA2-93272933D086</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-4s</key>
        <string>73837B7E-8E11-4616-AE13-23F60728FBF3</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5</key>
        <string>2E3268E4-2E35-44BC-AF3D-F32306D44F13</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5s</key>
        <string>C8ECDF4C-DE68-4A73-9ECA-546E85A3DA80</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6</key>
        <string>8E37DC02-393F-4695-980C-8679A5D56E46</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus</key>
        <string>BB59A82C-BC47-4B51-A3B8-F0123394292A</string>
    </dict>
    <key>com.apple.CoreSimulator.SimRuntime.iOS-8-1</key>
    <dict>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPad</key>
        <string>95254D91-345C-446E-8CC7-72382C0AB8AD</string>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPhone</key>
        <string>1E16E2F4-BC24-4F3D-AB1F-C07A6FA52E6F</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-2</key>
        <string>3B316D24-6497-45C1-BE0D-690FA831D6A3</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Air</key>
        <string>52AE24F1-92AE-4198-A196-32A4691903D8</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Retina</key>
        <string>55ED45DA-3ACB-479C-9FF9-F0905B47A497</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-4s</key>
        <string>FE578030-E512-4643-9F28-FCDCCD74279F</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5</key>
        <string>9C328DC5-2E4F-47AB-ABBA-1C881DE48795</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5s</key>
        <string>8D91EB18-594B-4288-BBF4-BF2655308706</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6</key>
        <string>53510FD4-EEE0-487E-B20E-F9F8AC65BA57</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus</key>
        <string>70F1B2D6-966D-49F0-B6CE-BCF995F425CB</string>
    </dict>
    <key>com.apple.CoreSimulator.SimRuntime.iOS-8-2</key>
    <dict>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPad</key>
        <string>27E051F5-F718-4BDC-99AA-F8C66B66505E</string>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPhone</key>
        <string>C56D2AC5-9F7A-4C8B-BCED-997A32D7342B</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-2</key>
        <string>180A9123-2F6C-423D-A124-CAAEEC8661D5</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Air</key>
        <string>57E7ED1B-89BB-4C0E-A167-7D6FDD97E838</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Retina</key>
        <string>0BBD9657-498C-4823-BA0B-4A5EA7305224</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-4s</key>
        <string>4370C11F-7486-4E16-AD62-04BC6ECF23CC</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5</key>
        <string>1635F9A2-5CD6-4669-B69B-493EDA2736BF</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5s</key>
        <string>AD9B417C-BB60-4A94-A080-4E9A00577762</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6</key>
        <string>44F34FBC-924E-4226-AF8B-C9C76C618457</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus</key>
        <string>A1575F64-44E1-4999-985E-88B890354A36</string>
    </dict>
    <key>com.apple.CoreSimulator.SimRuntime.iOS-8-3</key>
    <dict>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPad</key>
        <string>726D5E5A-A5C2-4EEA-B18E-C5174AE7EFD4</string>
        <key>com.apple.CoreSimulator.SimDeviceType.Resizable-iPhone</key>
        <string>14E7FDD6-751B-4A81-9CAF-B7F8359C553F</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-2</key>
        <string>79272BA7-45B9-47C4-A74E-91A9A1C02141</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Air</key>
        <string>FE7A9682-FF80-4F7E-9817-A1B2CFDA0328</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPad-Retina</key>
        <string>E45166AD-7ED3-4001-B01C-3B8F8497ECEA</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-4s</key>
        <string>DB987632-15E5-4CB4-B20C-1FF8FF4606C6</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5</key>
        <string>E1F83FA1-F630-4CDB-9E2D-8792797BEA5E</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-5s</key>
        <string>57028519-A154-4768-87D7-589111236C12</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6</key>
        <string>ACE62A2C-E3E0-408F-A198-983D244107E7</string>
        <key>com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus</key>
        <string>A4526FAE-721D-488F-B9F6-D0D6A31EE579</string>
    </dict>
    <key>version</key>
    <integer>0</integer>
</dict>
</plist>

回答1:

This can happen if you renamed or moved Xcode.app. Try renaming it back to what it was before or rebooting. If that doesn't address the issue, your should look at 'xcrun simctl list' and ~/Library/Developer/CoreSimulator/Devices to see if you have any devices.

Also check out ~/Library/Logs/CoreSimulator for any error logs.

From the added logging and information provided, the issue is that you had iOS 8.3 devices created for you at some point (that is why the UUIDs appear in the . default_created.plist file), but their device.plist files got deleted, so the system is (correctly) no longer listing them.

I'm not sure how the device.plist files got deleted from your system, but you can go back to a vanilla state with:

sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
rm -rf ~/Library/*/CoreSimulator

回答2:

Try This...
1.Run the simulator from application(Or from spotlight)
2.Hardware ----> Device---> Manage Device.
3.A popup will open, in that screen bottom left corner you will find "+" use + for adding new simulators for different ios versions

回答3:

In my case, I downloaded simulators of version iOS 8.2 and in project iOS deployment target was higher than downloaded version so it was not showing, once you will change it lower than downloaded version it will start to show. Please, let me know if you are facing any issue.