SQL Server Management Studio 18 won't open (only splash screen pops up) I just installed SSMS 18 GA on a computer with only VS2019 installed, and when I try to open SSMS the splash screen will come up, but then the process exits.  

Running ssms with the -log parameter reveals an error message:


  CreateInstance failed for package [Task Scheduler Package]Source:
  'mscorlib' Description: Could not load file or assembly
  'Microsoft.VisualStudio.Shell.Interop.8.0, Version=15.0.0.0,
  Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its
  dependencies. The located assembly's manifest definition does not
  match the assembly reference. (Exception from HRESULT: 0x80131040)
  System.IO.FileLoadException: Could not load file or assembly
  'Microsoft.VisualStudio.Shell.Interop.8.0, Version=15.0.0.0,
  Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its
  dependencies. The located assembly's manifest definition does not
  match the assembly reference. (Exception from HRESULT: 0x80131040)
  File name: 'Microsoft.VisualStudio.Shell.Interop.8.0,
  Version=15.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
  ---> System.IO.FileLoadException: Could not load file or assembly 'Microsoft.VisualStudio.Shell.Interop.8.0, Version=8.0.0.0,
  Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its
  dependencies. The located assembly's manifest definition does not
  match the assembly reference. (Exception from HRESULT: 0x80131040)
  File name: 'Microsoft.VisualStudio.Shell.Interop.8.0, Version=8.0.0.0,
  Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
  
  WRN: Assembly binding logging is turned OFF. To enable assembly bind
  failure logging, set the registry value
  [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There
  is some performance penalty associated with assembly bind failure
  logging. To turn this feature off, remove the registry value
  [HKLM\Software\Microsoft\Fusion!EnableLog].
  
  at System.Reflection.RuntimeAssembly.GetType(RuntimeAssembly
  assembly, String name, Boolean throwOnError, Boolean ignoreCase,
  ObjectHandleOnStack type)    at
  System.Reflection.RuntimeAssembly.GetType(String name, Boolean
  throwOnError, Boolean ignoreCase)    at
  System.Activator.CreateInstance(String assemblyString, String
  typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder,
  Object[] args, CultureInfo culture, Object[] activationAttributes,
  Evidence securityInfo, StackCrawlMark&amp; stackMark)    at
  System.Activator.CreateInstance(String assemblyName, String typeName) 
  at System.AppDomain.CreateInstance(String assemblyName, String
  typeName)
  
  System.IO.FileLoadException: Could not load file or assembly
  'Microsoft.VisualStudio.Shell.Interop.8.0, Version=8.0.0.0,
  Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its
  dependencies. The located assembly's manifest definition does not
  match the assembly reference. (Exception from HRESULT: 0x80131040)
  File name: 'Microsoft.VisualStudio.Shell.Interop.8.0, Version=8.0.0.0,
  Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
  
  WRN: Assembly binding logging is turned OFF. To enable assembly bind
  failure logging, set the registry value
  [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There
  is some performance penalty associated with assembly bind failure
  logging. To turn this feature off, remove the registry value
  [HKLM\Software\Microsoft\Fusion!EnableLog].


I tried running "Repair" on SSMS, and tried a repair of C:\ProgramData\Package Cache\{AAA9F15B-AF45-4562-9991-93A848D3A902}v15.0.28307.421\redist\vs2017_isoshell_for_ssms.msi, but the problem persists.
I just overlaid the Microsoft.VisualStudio.Shell.Interop.8.0.dll in C:\Program Files (x86)\Microsoft SQL Server Management Studio 18\Common7\IDE\PublicAssemblies with the copy from ..\PrivateAssemblies\Interop and the IDE opens. (Thanks to Mitch for discovering the offending DLL name.) 

This looks like a popular Q &amp; A today, so I'm glad to know this wasn't just me.