Debug SharePoint solutions
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
You can debug SharePoint solutions by using the Visual Studio debugger. When you start debugging, Visual Studio deploys the project files to the SharePoint server and then opens an instance of the SharePoint site in the Web browser. The following sections explain how to debug SharePoint applications in Visual Studio.
Enable debugging
When you first debug a SharePoint solution in Visual Studio, a dialog box alerts you that the web.config file is not configured to enable debugging. (The web.config file is created when you install SharePoint server. For more information, see Working with Web.config Files.) The dialog box gives you the option of either running the project without debugging or modifying the web.config file to enable debugging. If you choose the first option, the project runs normally. If you choose the second option, the web.config file is configured to:
Turn on the call stack (
CallStack="true")Disable custom errors in Visual Studio (
<customErrors mode="Off" />)Enable compilation debugging (
<compilation debug="true">)The resulting web.config file follows:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<configuration>
...
<SharePoint>
<SafeMode MaxControls="200"
CallStack="true"
DirectFileDependencies="10"
TotalFileDependencies="50"
AllowPageLevelTrace="false">
...
</SafeMode>
...
</SharePoint>
<system.web>
...
<customErrors mode="Off" />
...
<compilation debug="true">
...
</compilation>
...
</system.web>
...
</configuration>
To reverse the changes and disable debugging, change the following XML in the web.config file:
Turn off the call stack (
CallStack="false")Enable custom errors in Visual Studio (
<customErrors mode="On" />)Disable compilation debugging (
<compilation debug="false">)
F5 debug and deployment process
When you run your SharePoint project in debug mode, the SharePoint deployment process performs the following tasks:
Runs the customizable pre-deployment commands.
Creates a Web solution package (.wsp) file by using MSBuild commands. The .wsp file includes all of the necessary files and features. For more information, see Solutions Overview.
If the SharePoint solution is a farm solution, recycles the IIS application pool for the specified site URL. This step releases files locked by the IIS worker process.
If a previous version of the package already exists, retracts the previous version of the features and files in the .wsp file. This step deactivates the features, uninstalls the solution package, and then deletes the solution package on the SharePoint server.
Installs the current version of the features and files in the .wsp file. This step adds and installs the solution on the SharePoint server.
For workflows, installs the workflow assembly. You can change its location by using the Assembly Location property.
Activates the project's feature in SharePoint if the scope is Site or Web. Features in the Farm and WebApplication scopes are not activated.
For workflows, associates the workflow with the SharePoint library, list, or site that you selected in the SharePoint Customization Wizard.
Note
This association occurs only if you selected Automatically associate workflow in the wizard.
Runs the customizable post-deployment commands.
Attaches the Visual Studio debugger to the Windows SharePoint Services process (w3wp.exe). If the project type lets you change the Sandboxed Solution property and its value is set to true, then the debugger attaches to a different process (SPUCWorkerProcess.exe). For more information, see Sandboxed solution considerations.
Starts the JavaScript debugger if the SharePoint solution is a farm solution.
Displays the appropriate library, list, or site page in the Web browser.
Visual Studio displays a status message in the Output window after each task is completed. If a task cannot be completed, Visual Studio displays an error message in the Error List window.
SharePoint project features
A feature is a portable and modular unit of functionality that simplifies modification of sites by using site definitions. It is also a package of Windows SharePoint Services (WSS) elements that can be activated for a specific scope and that helps users accomplish a particular goal or task. Templates are deployed as features.
When you run a project in debug mode, the deployment process creates a folder in the feature directory at %COMMONPROGRAMFILES%\Microsoft Shared\web server extensions\14\TEMPLATE\FEATURES. Feature names have the format project name_Featurex, such as TestProject_Feature1.
The solution's folder in the feature directory contains a feature definition file and a workflow definition file. The feature definition file (Feature.xml) describes the files in the project's Feature.The project definition file (Elements.xml) describes the project template. Elements.xml can be found in Solution Explorer, but Feature.xml is generated when the solution package is created. For more information about these files, see SharePoint project and project item templates.
Debug workflows
When you debug workflow projects, Visual Studio adds the workflow template (depending on its type) to a library or to a list. You can then start the workflow template manually or by adding or updating an item. You can then use Visual Studio to debug the workflow.
Note
If you add references to other assemblies, make sure that those assemblies are installed in the global assembly cache ( GAC). Otherwise, the workflow solution will fail. For information about how to install assemblies, see Manually start a workflow on a document or item.
However, the deployment process does not start the workflow. You must start the workflow from the SharePoint Web site. You can also start the workflow by using a client application such as Microsoft Office Word 2010, or by using separate server-side code. Use one of the approaches specified in the SharePoint Customization Wizard.
For example, if you specified that the workflow can be started manually, start the workflow directly from the item in the library or list. For more information about how to start a workflow manually, see Manually start a workflow on a document item.
Debug feature event receivers
By default, when you run a Visual Studio SharePoint application, its features are automatically activated for you on the SharePoint server. However, this causes problems when you debug feature event receivers, because when a feature is activated by Visual Studio, it runs in a different process than the debugger. This means that some debugging functionality, such as breakpoints, will not work correctly.
To disable the automatic activation of the feature in SharePoint and allow proper debugging of Feature Event Receivers, set the value of the project's Active Deployment Configuration property to No Activation before debugging. Then, after you start to debug your SharePoint application in Visual Studio, manually activate the feature in SharePoint. To activate the feature, open the Site Actions menu in SharePoint, choose Site Settings, choose the Manage Site Features link, and then choose the Activate button next to the feature, to continue debugging as normal.
Enable enhanced debugging information
Due to the sometimes complex interactions between the Visual Studio process (devenv.exe), the Visual Studio SharePoint host process (vssphost4.exe), SharePoint, and the WCF layer, diagnosing errors that occur while building, deploying, and so forth can be a challenge. To help you resolve such errors, you can enable enhanced debugging information. To do this, go to the following registry key in the Windows registry:
HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\11.0\SharePointTools
If the "EnableDiagnostics" REG_DWORD value does not already exist, create it manually. Set the "EnableDiagnostics" value to "1."
Setting this key value to 1 causes stack trace information to appear in the Output window whenever project system errors occur while you are running in Visual Studio. To disable enhanced debugging information, set EnableDiagnostics back to 0, or delete the value.
For more information about other SharePoint registry keys, see Debug extensions for the SharePoint tools in Visual Studio.