I'm attempting to upgrade from version 7.1.6 to the latest 7.4.3 via Nuget. I've run into a series of roadblocks that I'm not having any luck working around. Any advice would be appreciated.

I've followed the upgrade instructions. I made a backup of my database, checked everything into source control, etc. I did the upgrade via nuget and that all works fine. The problems start when I try to run the project and actually do the upgrade (local dev environment: Windows 7, VS 2013, IIS Express, SQL Server 2014).

The first issue is with logging into Umbraco to Authorize the upgrade. I provide my admin login credentials at which point I run into the issue detailed here. No one seems to have addressed that yet, so I sought a workaround. I found that by removing the umbracoDbDSN connection string information in my web.config I could force it to act like a new install. The installer then allowed me to point at my local database (basically just provide the information from the umbracoDbDSN connection string) and begin the installation.

Unfortunately it fails every time. I end up with a variant of this in my logs:

2016-07-01 15:20:29,785 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 24 Items 0 changes 0 failures
2016-07-01 15:20:29,846 [20] INFO  Jumoo.uSync.BackOffice.Logging - Running Import: Template
2016-07-01 15:20:29,923 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 14 Items 0 changes 0 failures
2016-07-01 15:20:29,983 [20] INFO  Jumoo.uSync.BackOffice.Logging - Running Import: DocumentType
2016-07-01 15:20:30,262 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 14 Items 0 changes 0 failures
2016-07-01 15:20:30,318 [20] INFO  Jumoo.uSync.BackOffice.Logging - Running Import: MediaType
2016-07-01 15:20:30,417 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 3 Items 0 changes 0 failures
2016-07-01 15:20:30,466 [20] INFO  Jumoo.uSync.BackOffice.Logging - Running Import: Languages
2016-07-01 15:20:30,549 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 1 Items 0 changes 0 failures
2016-07-01 15:20:30,614 [20] INFO  Jumoo.uSync.BackOffice.Logging - Running Import: DictionaryItem
2016-07-01 15:20:30,680 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 0 Items 0 changes 0 failures
2016-07-01 15:20:30,747 [20] INFO  Jumoo.uSync.BackOffice.Logging - Running Import: macro
2016-07-01 15:20:30,800 [20] INFO  Jumoo.uSync.BackOffice.Logging - Handler Import Complete: 0 Items 0 changes 0 failures
2016-07-01 15:20:30,875 [20] INFO  Jumoo.uSync.BackOffice.uSyncApplicationEventHandler - Setting up Events
2016-07-01 15:20:30,939 [20] INFO  Jumoo.uSync.BackOffice.uSyncAction - ### uSync.BackOffice Processed 56 items with 0 changes ###
2016-07-01 15:20:31,004 [20] INFO  Jumoo.uSync.BackOffice.uSyncApplicationEventHandler - uSync Complete (3244ms)
2016-07-01 15:20:31,086 [20] INFO  Umbraco.Core.CoreBootManager - Umbraco application startup complete (took 17765ms)
2016-07-01 15:20:33,842 [20] INFO  Umbraco.Core.Sync.ApplicationUrlHelper - ApplicationUrl: http://{LOCAL DOMAIN}.local:50285/umbraco (UmbracoModule request)
2016-07-01 15:20:40,071 [10] INFO  Umbraco.Core.UmbracoApplicationBase - Application shutdown. Details: ConfigurationChange

_shutDownMessage=CONFIG change
HostingEnvironment initiated shutdown
CONFIG change
CONFIG change
CONFIG change
HostingEnvironment caused shutdown

_shutDownStack=   at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
   at System.Environment.get_StackTrace()
   at System.Web.Hosting.HostingEnvironment.InitiateShutdownInternal()
   at System.Web.Hosting.HostingEnvironment.InitiateShutdownWithoutDemand()
   at System.Web.HttpRuntime.ShutdownAppDomain(String stackTrace)
   at System.Web.Configuration.HttpConfigurationSystem.OnConfigurationChanged(Object sender, InternalConfigEventArgs e)
   at System.Configuration.Internal.InternalConfigRoot.OnConfigChanged(InternalConfigEventArgs e)
   at System.Configuration.BaseConfigurationRecord.OnStreamChanged(String streamname)
   at System.Web.Configuration.WebConfigurationHostFileChange.OnFileChanged(Object sender, FileChangeEvent e)
   at System.Web.DirectoryMonitor.FireNotifications()
   at System.Web.Util.WorkItem.CallCallbackWithAssert(WorkItemCallback callback)
   at System.Web.Util.WorkItem.OnQueueUserWorkItemCompletion(Object state)
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
2016-07-01 15:21:34,200 [14] INFO  umbraco.BusinessLogic.Log - Log scrubbed.  Removed all items older than 2016-06-30 15:21:34

Interestingly, I've seen instances where the "HostingEnvironment initiated shutdown" message occurs in the log but does not stop the installation. However, the install never completes; the shutdown happens again and appears terminal.

At that point, the main site loads rather than the install screen. However, I'm unable to login to the back office. Additionally, if I try to tell the installer to "go back" and then "Continue" I get a "Could not connect to database" error on the UI, which is just an obfuscation of the underlying

{"Message":"Authorization has been denied for this request."}

error that is actually returned. I'm able to see that error in Fiddler.

Assuming this might be an environmental issue I deployed the upgraded code to our Staging environment (Windows Server 2012, IIS 8, Sql Server 2014) and got the same "HostingEnvironment initiated shutdown" behavior.

I'm stumped. Any suggestions on what to try next would be greatly appreciated.