I have finally managed to migrate my v7 db to v8 after 3 days of working going through issues! Unfortunately at this point I have a new problem; Umbraco now won't start and gives the error below. There is no more info in the log file other than the same exception message. I have only a blank 8.5 project installed from Nuget, nothing else added yet. Any help greatly appreciated!

Boot failed: Umbraco cannot run. See Umbraco's log file for more details.

-> Umbraco.Core.Exceptions.BootFailedException: Boot failed.

-> System.IO.InvalidDataException: Found invalid data while decoding.
  at Check.Assert[TException](Boolean condition)
  at CSharpTest.Net.Serialization.PrimitiveSerializer.CSharpTest.Net.Serialization.ISerializer<System.UInt32>.ReadFrom(Stream stream)
  at CSharpTest.Net.Storage.BTreeFileStoreV2.CSharpTest.Net.Serialization.ISerializer<CSharpTest.Net.Collections.IStorageHandle>.ReadFrom(Stream stream)
  at CSharpTest.Net.Collections.BPlusTree`2.StorageCache.CSharpTest.Net.Serialization.ISerializer<CSharpTest.Net.Collections.IStorageHandle>.ReadFrom(Stream stream)
  at CSharpTest.Net.Collections.BPlusTree`2.NodeHandleSerializer.CSharpTest.Net.Serialization.ISerializer<CSharpTest.Net.Collections.IStorageHandle>.ReadFrom(Stream stream)
  at
....

  at LightInject.ServiceContainer.<>c__DisplayClass153_0.<CreateEmitMethodWrapper>b__0(IEmitter ms) in C:\projects\lightinject\src\LightInject\LightInject.cs:line 3856
  at LightInject.ServiceContainer.CreateDynamicMethodDelegate(Action`1 serviceEmitter) in C:\projects\lightinject\src\LightInject\LightInject.cs:line 3776
  at LightInject.ServiceContainer.CreateDelegate(Type serviceType, String serviceName, Boolean throwError) in C:\projects\lightinject\src\LightInject\LightInject.cs:line 4743
  at LightInject.ServiceContainer.CreateDefaultDelegate(Type serviceType, Boolean throwError) in C:\projects\lightinject\src\LightInject\LightInject.cs:line 4705
  at LightInject.ServiceContainer.GetInstance(Type serviceType) in C:\projects\lightinject\src\LightInject\LightInject.cs:line 3437
  at Umbraco.Core.Composing.LightInject.LightInjectContainer.GetInstance(Type type) in d:\a\1\s\src\Umbraco.Core\Composing\LightInject\LightInjectContainer.cs:line 111
  at Umbraco.Core.FactoryExtensions.GetInstance[T](IFactory factory) in d:\a\1\s\src\Umbraco.Core\FactoryExtensions.cs:line 22
  at Umbraco.Core.Runtime.CoreRuntime.Boot(IRegister register, DisposableTimer timer) in d:\a\1\s\src\Umbraco.Core\Runtime\CoreRuntime.cs:line 158