“Unknown Error” in SharePoint – Causes, Troubleshooting, and Solutions

The “Unknown Error” in SharePoint is a vague and generic error message that does not provide specific details about what went wrong. It can occur due to various reasons, including misconfigured settings, permission issues, database corruption, server-side errors, or missing dependencies.

Since the message itself is not informative, the best way to diagnose the issue is by checking SharePoint logs, event viewer logs, and IIS logs to pinpoint the root cause.

📌 In this detailed guide, we will cover:

✅ What causes the “Unknown Error” in SharePoint?
✅ How to check server logs and error messages?
✅ Step-by-step troubleshooting methods to fix the issue.

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🚨 Common Causes of “Unknown Error” in SharePoint

1️⃣ Insufficient Permissions

• The user may not have the required permissions to access a specific site or resource.
• The error can appear if a user tries to perform an action without the necessary privileges.

2️⃣ Corrupt or Misconfigured Web.config File

• If the Web.config file is corrupt or incorrectly modified, SharePoint may throw an unknown error.
• This can happen after a manual edit or update.

3️⃣ SharePoint Features or Solutions Not Activated Properly

• If a custom feature, web part, or solution is not deployed or activated correctly, it may cause unexpected errors.

4️⃣ Database Connectivity Issues

• If SharePoint cannot connect to the SQL Server database, it may result in an unknown error.
• Possible causes include database corruption, permissions, or network issues.

5️⃣ IIS and Application Pool Issues

• The SharePoint site may be experiencing issues due to an IIS misconfiguration or stopped application pool.

6️⃣ Corrupt SharePoint Cache or Configuration Issues

• If SharePoint cache files are outdated or corrupted, it can lead to unexplained errors.

7️⃣ Recent SharePoint Updates or Patches

• A recent Windows or SharePoint update may have introduced compatibility issues, causing unknown errors.

8️⃣ Missing or Corrupt Dependencies

• If SharePoint relies on third-party components, APIs, or .NET Framework versions that are missing or outdated, the error may occur.

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🛠 How to Fix “Unknown Error” – Step-by-Step Guide

Since there are multiple potential causes, follow the steps below systematically to diagnose and fix the issue.

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🔍 Step 1: Enable Detailed Error Messages in SharePoint

By default, SharePoint hides detailed error messages for security reasons. To get more information, we need to enable verbose error reporting.

✅ How to Enable Verbose Errors in SharePoint (Web.config File)

1. Log in to the SharePoint server.
2. Navigate to the following directory: C:\inetpub\wwwroot\wss\VirtualDirectories\[YourSitePort]\
3. Find and open Web.config in a text editor (Notepad++ or Visual Studio Code).
4. Locate the following line: <customErrors mode="On" /> Change it to: <customErrors mode="Off" />
5. Locate the CallStack setting and change: <SafeMode MaxControls="200" CallStack="false" /> To: <SafeMode MaxControls="200" CallStack="true" />
6. Save the Web.config file and restart IIS: iisreset /noforce

✅ Now, when you refresh the SharePoint page, you should see a more detailed error message instead of “Unknown Error”.

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🔍 Step 2: Check SharePoint ULS Logs for Detailed Errors

SharePoint logs errors in Unified Logging System (ULS) logs, which contain more details about the issue.

✅ How to Check ULS Logs for Errors

1. Open PowerShell as Administrator.
2. Run the following command to view the latest errors: Get-SPLogLevel
3. To get more details, run: Get-SPLogLevel | Format-Table -AutoSize
4. Navigate to the ULS log directory: C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\LOGS (For SharePoint 2013, replace 16 with 15).
5. Open the most recent log file in ULS Viewer and look for Critical or Unexpected errors.

✅ These logs should provide more information about what caused the unknown error.

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🔍 Step 3: Check Windows Event Viewer for Errors

Errors related to SharePoint are also logged in Windows Event Viewer.

✅ How to Check Event Viewer Logs for SharePoint Errors

1. Press Win + R, type eventvwr.msc, and hit Enter.
2. Navigate to Windows Logs → Application.
3. Look for errors related to SharePoint, IIS, or SQL Server.

✅ This helps identify issues like database failures, IIS crashes, or missing dependencies.

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🔍 Step 4: Verify IIS and SharePoint Application Pools

If SharePoint’s IIS application pool is stopped, it can trigger unknown errors.

✅ How to Restart IIS and SharePoint Application Pools

1. Open IIS Manager (inetmgr).
2. Expand Sites → SharePoint Web Application.
3. Click Application Pools.
4. Check if the SharePoint app pool is stopped. If yes, right-click → Start.
5. Restart IIS using: iisreset /noforce

✅ This ensures that the SharePoint site is running properly.

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🔍 Step 5: Verify SharePoint Service Applications and Features

If certain service applications are misconfigured, SharePoint may throw errors.

✅ How to Check and Restart Services in SharePoint Central Admin

1. Open SharePoint Central Administration.
2. Go to System Settings → Manage Services on Server.
3. Ensure that all required services are running.
4. Restart any stopped services like:
   • SharePoint Timer Service
   • Search Service Application
   • Managed Metadata Service

✅ This helps resolve service-related unknown errors.

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🔍 Step 6: Verify SQL Server and Database Connectivity

If SharePoint cannot connect to its database, it may return an unknown error.

✅ How to Check SQL Server Connection

1. Open SQL Server Management Studio (SSMS).
2. Run the following query: SELECT name, state_desc FROM sys.databases;
3. Ensure that all SharePoint databases are in the ONLINE state.
4. If the database is in READ-ONLY mode, change it using: ALTER DATABASE [DatabaseName] SET READ_WRITE;

✅ This ensures SharePoint can access and write to its databases.

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