Could not find configuration node: databases/database[@id='core']

Question

Im new to Sitecore and I'm trying to get create a new instance for a existing solution. I think I have it almost built but I'm running into a issue when I use the default route of "/sitecore".

Im getting the following error.

Could not find configuration node: databases/database[@id='core']

I believe my connection strings are correct.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.InvalidOperationException: Could not find configuration node: databases/database[@id='core']

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 


[InvalidOperationException: Could not find configuration node: databases/database[@id='core']]
   Sitecore.Configuration.DefaultFactory.GetConfigNode(String xpath, Boolean assert) +502
   Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert) +273
   Sitecore.Configuration.DefaultFactory.GetDatabase(String name, Boolean assert) +177
   Sitecore.Configuration.DefaultFactory.GetDatabase(String name) +55
   Sitecore.DefaultClient.get_CoreDatabase() +23
   Sitecore.Security.SecurityHelper.CanRunApplication(String applicationName) +203
   Sitecore.DefaultPage.Page_Load(Object sender, EventArgs e) +249
   System.Web.UI.Control.OnLoad(EventArgs e) +103
   System.Web.UI.Control.LoadRecursive() +68
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1381

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.2556.0

Im running Sitecore 8.2.

Thank you ahead of time for any help.

Answer 1

Most probably you overwrote the default web.config accidentally. If not the web.config has overwritten then another default Sitecore config patched incorrectly or completely removed.

How to fix

Compare the configurations with a default clean Sitecore install.

Possible reason of the overwrite

What I see usually is that Visual Studio adds a web.config automatically to the project with Content Build Action.

If you deploy the project then it overwrites the Sitecore default web.config.

Note: Same could happen with Global.asax, do not overwrite it, use the initialize pipeline instead.

If you need changes in web.config

Then first copy the default Sitecore web.config to your Visual Studio solution and change it.