How to reproduce:

1. Open attached project
2. Build project to iOS and run
- Leave the iOS build running on device
3. Clone and open project from https://bitbucket.org/Unity-Technologies/memoryprofiler
4. Open the Profiler window
5. Attach the profiler to the device running the original project
6. Go to Window -> MemoryProfiler
7. Click Take Snapshot
- Note the error that's thrown in the editor:

KeyNotFoundException: The given key was not present in the dictionary.
at System.Collections.Generic.Dictionary`2[System.UInt64,UnityEditor.MemoryProfiler.TypeDescription].get_Item (UInt64 key) [0x000a2] in /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:150
at MemoryProfilerWindow.Crawler.ParseObjectHeader (MemoryProfilerWindow.StartIndices startIndices, UnityEditor.MemoryProfiler.MemorySection[] heap, UInt64 originalHeapAddress, System.UInt64& typeInfoAddress, System.Int32& indexOfObject, System.Boolean& wasAlreadyCrawled, System.Collections.Generic.List`1 outManagedObjects) [0x00042] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/Crawler.cs:211
at MemoryProfilerWindow.Crawler.CrawlPointer (UnityEditor.MemoryProfiler.PackedMemorySnapshot packedMemorySnapshot, MemoryProfilerWindow.StartIndices startIndices, UInt64 pointer, Int32 indexOfFrom, System.Collections.Generic.List`1 out_connections, System.Collections.Generic.List`1 out_managedObjects) [0x00020] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/Crawler.cs:154
at MemoryProfilerWindow.Crawler.CrawlPointer (UnityEditor.MemoryProfiler.PackedMemorySnapshot packedMemorySnapshot, MemoryProfilerWindow.StartIndices startIndices, UInt64 pointer, Int32 indexOfFrom, System.Collections.Generic.List`1 out_connections, System.Collections.Generic.List`1 out_managedObjects) [0x0011a] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/Crawler.cs:181
at MemoryProfilerWindow.Crawler.CrawlRawObjectData (UnityEditor.MemoryProfiler.PackedMemorySnapshot packedMemorySnapshot, MemoryProfilerWindow.StartIndices startIndices, BytesAndOffset bytesAndOffset, TypeDescription typeDescription, Boolean useStaticFields, Int32 indexOfFrom, System.Collections.Generic.List`1 out_connections, System.Collections.Generic.List`1 out_managedObjects) [0x00128] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/Crawler.cs:140
at MemoryProfilerWindow.Crawler.CrawlPointer (UnityEditor.MemoryProfiler.PackedMemorySnapshot packedMemorySnapshot, MemoryProfilerWindow.StartIndices startIndices, UInt64 pointer, Int32 indexOfFrom, System.Collections.Generic.List`1 out_connections, System.Collections.Generic.List`1 out_managedObjects) [0x00079] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/Crawler.cs:165
at MemoryProfilerWindow.Crawler.Crawl (UnityEditor.MemoryProfiler.PackedMemorySnapshot input) [0x0009e] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/Crawler.cs:31
at MemoryProfilerWindow.MemoryProfilerWindow.IncomingSnapshot (UnityEditor.MemoryProfiler.PackedMemorySnapshot snapshot) [0x00017] in /Users/ayunoshev/GameInsight/Projects/memoryprofiler/Assets/Editor/MemoryProfilerWindow.cs:159
at UnityEditor.MemoryProfiler.MemorySnapshot.DispatchSnapshot (UnityEditor.MemoryProfiler.PackedMemorySnapshot snapshot) [0x0000c] in /Users/builduser/buildslave/unity/build/Editor/Mono/Profiler/MemorySnapshot.cs:24

(Filename: /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs Line: 150)

- Reproduced in Version 5.3.0f4 (2524e04062b4)
- Project crashes on startup on device in Version 5.4.0a5 (6b220773f9c9)
- Blocked from testing older versions
- The issue only happens with the provided project. Using any other project does not yield the issue.