Hi!
I ios game building have this error.
Help me Please 
Exception Name: NSInvalidArgumentException
Description: -[NSURL length]: unrecognized selector sent to instance 0x114ad2550
User Info: (null)
0 CoreFoundation 0x00007fff94aefb5c __exceptionPreprocess + 172
1 libobjc.A.dylib 0x00007fff92e798e8 objc_exception_throw + 48
2 CoreFoundation 0x00007fff94af2c1d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x00007fff94a2c4c1 forwarding + 1009
4 CoreFoundation 0x00007fff94a2c048 _CF_forwarding_prep_0 + 120
5 Foundation 0x00007fff94f505bd -[NSFileManager fileExistsAtPath:] + 60
6 Unity 0x0000000101c8386b -[AppendSavePanel _overwriteExistingFileCheck:] + 59
7 AppKit 0x00007fff8cb62ac7 -[NSSavePanel _okForSaveMode] + 317
8 AppKit 0x00007fff8cb6385b -[NSSavePanel ok:] + 211
9 libsystem_trace.dylib 0x00007fff8d12d259 _os_activity_initiate + 75
10 AppKit 0x00007fff8c70bf68 -[NSApplication sendAction:to:from:] + 460
11 AppKit 0x00007fff8c720de6 -[NSControl sendAction:to:] + 86
12 AppKit 0x00007fff8c720d10 __26-[NSCell _sendActionFrom:]_block_invoke + 131
13 libsystem_trace.dylib 0x00007fff8d12d259 _os_activity_initiate + 75
14 AppKit 0x00007fff8c720c6d -[NSCell _sendActionFrom:] + 144
15 libsystem_trace.dylib 0x00007fff8d12d259 _os_activity_initiate + 75
16 AppKit 0x00007fff8c71f292 -[NSCell trackMouse:inRect:ofView:untilMouseUp:] + 2693
17 AppKit 0x00007fff8c7743c2 -[NSButtonCell trackMouse:inRect:ofView:untilMouseUp:] + 744
18 AppKit 0x00007fff8c71d9c7 -[NSControl mouseDown:] + 657
19 AppKit 0x00007fff8ccbad5b -[NSWindow _handleMouseDownEvent:isDelayedEvent:] + 6039
20 AppKit 0x00007fff8ccbc01f -[NSWindow _reallySendEvent:isDelayedEvent:] + 150
21 AppKit 0x00007fff8c625056 -[NSWindow sendEvent:] + 494
22 AppKit 0x00007fff8c6217b9 -[NSApplication sendEvent:] + 2561
23 Unity 0x0000000101c926f1 -[EditorApplicationPrincipalClass sendEvent:] + 209
24 AppKit 0x00007fff8c713724 -[NSApplication _realDoModalLoop:peek:] + 731
25 AppKit 0x00007fff8c70fcf0 -[NSApplication runModalForWindow:] + 125
26 AppKit 0x00007fff8cb61888 -[NSSavePanel runModal] + 407
27 Unity 0x0000000101c834f2 _Z29RuniPhoneReplaceOrAppendPanelRKSsS0_S0_Pb + 210
28 Unity 0x0000000101ad7b0d _Z17RunSaveBuildPanel19BuildTargetPlatformRKSsS1_S1_S1_Pb + 45
29 Unity 0x000000010238fea1 _Z35EditorUtility_CUSTOM_SaveBuildPanel19BuildTargetPlatform11ICallStringS0_S0_S0_Ph + 177
30 ??? 0x000000011bfbf5e9 0x0 + 4764464617
31 ??? 0x000000011bfbe96f 0x0 + 4764461423
32 ??? 0x000000011bfbd9ea 0x0 + 4764457450
33 ??? 0x000000011bfbcaca 0x0 + 4764453578
34 ??? 0x000000011bfbaad2 0x0 + 4764445394
35 ??? 0x000000011bfb54d2 0x0 + 4764423378
36 ??? 0x0000000118176301 0x0 + 4699153153
37 ??? 0x000000011c87b97a 0x0 + 4773624186
38 libmono.0.dylib 0x0000000109c3bb9c mono_get_runtime_build_info + 3694
39 libmono.0.dylib 0x0000000109d5faef mono_runtime_invoke + 114
40 libmono.0.dylib 0x0000000109d657e1 mono_runtime_invoke_array + 841
41 libmono.0.dylib 0x0000000109d251ea mono_register_jit_icall + 36658
42 ??? 0x00000001211d7533 0x0 + 4850545971
43 ??? 0x00000001211d590c 0x0 + 4850538764
44 ??? 0x000000011c92b1a6 0x0 + 4774343078
45 ??? 0x000000012460ccfd 0x0 + 4905291005
46 ??? 0x000000012460cc00 0x0 + 4905290752
47 ??? 0x0000000118172bf7 0x0 + 4699139063
48 ??? 0x000000011c87b97a 0x0 + 4773624186
49 libmono.0.dylib 0x0000000109c3bb9c mono_get_runtime_build_info + 3694
50 libmono.0.dylib 0x0000000109d5faef mono_runtime_invoke + 114
51 Unity 0x00000001010e5117 _ZN25ScriptingInvocationNoArgs6InvokeEPP13MonoException + 103
52 Unity 0x00000001010c1c78 _ZN13MonoBehaviour5DoGUIENS_13GUILayoutTypeEi + 616
53 Unity 0x0000000101c87230 _ZN7GUIView12OnInputEventER10InputEvent + 752
54 Unity 0x0000000101c87b5a -[GUIOpenGLView mouseUp:] + 90
55 AppKit 0x00007fff8ccbb117 -[NSWindow _handleMouseUpEvent:isDelayedEvent:] + 119
56 AppKit 0x00007fff8ccbc01f -[NSWindow _reallySendEvent:isDelayedEvent:] + 150
57 AppKit 0x00007fff8c625056 -[NSWindow sendEvent:] + 494
58 AppKit 0x00007fff8c6217b9 -[NSApplication sendEvent:] + 2561
59 Unity 0x0000000101c926f1 -[EditorApplicationPrincipalClass sendEvent:] + 209
60 AppKit 0x00007fff8c55174e -[NSApplication run] + 796
61 AppKit 0x00007fff8c4d3b6d NSApplicationMain + 1176
62 Unity 0x0000000101c92dd6 _Z10EditorMainiPPKc + 1494
63 Unity 0x0000000101c93629 main + 9
64 Unity 0x0000000100002b54 start + 52