If you are Upgrading Umbraco from 7.2.X to 7.2.8 and Upgrading from MVC 4 to MVC 5.
Don't do both at the same time.
Upgrading MVC 4 to 5 will break the web.config in the views directory, which causes webapi to blow up, so the umbraco installer won't be able to run.
You won't have much information either as any attempt to go to your site will go to AuthorizeUpgrade and then blow up on Authentication\PostLogin with minimal error information "NullReference" Exception.
No fault on umbraco's part at all, just some friendly advice, don't Update-Package Microsoft.AspNet.Mvc and Update-Package UmbracoCms at the same time.
First upgrade umbraco to the latest version and run through the installer. Then upgrade MVC.
If you already did this. Create a fresh web app project, install UmbracoCms 7.2.8, then set the configuration version to 7.2.x (your old version) and copy your connection string from the old site.
The installer should run fine. Then update your old site's version in appsettings to 7.2.8 and it should load fine. and you should see mvc errors like referring to the wrong version of razor, or duplicate razor sections.
At which point you can update those and fix them now that the upgrade is done.
Upgrade Advice and MVC 5
If you are Upgrading Umbraco from 7.2.X to 7.2.8 and Upgrading from MVC 4 to MVC 5.
Don't do both at the same time.
Upgrading MVC 4 to 5 will break the web.config in the views directory, which causes webapi to blow up, so the umbraco installer won't be able to run.
You won't have much information either as any attempt to go to your site will go to AuthorizeUpgrade and then blow up on Authentication\PostLogin with minimal error information "NullReference" Exception.
No fault on umbraco's part at all, just some friendly advice, don't Update-Package Microsoft.AspNet.Mvc and Update-Package UmbracoCms at the same time.
First upgrade umbraco to the latest version and run through the installer. Then upgrade MVC.
If you already did this. Create a fresh web app project, install UmbracoCms 7.2.8, then set the configuration version to 7.2.x (your old version) and copy your connection string from the old site.
The installer should run fine. Then update your old site's version in appsettings to 7.2.8 and it should load fine. and you should see mvc errors like referring to the wrong version of razor, or duplicate razor sections.
At which point you can update those and fix them now that the upgrade is done.
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