Hey Dev! As a developer, you’re no stranger to running into SQL Server errors. They can be frustrating and time-consuming, but there’s always a way to fix them. In this article, we’ve collected 20 of the most common SQL Server errors and provided in-depth solutions to help you get back on track.
1. Error 18456: Login Failed for User
Error 18456 is a login-related error that occurs when a user fails to authenticate while attempting to connect to SQL Server. There are various reasons why this error might occur, including incorrect username or password, SQL Server authentication mode, or incorrect server name. Below are some steps to help you troubleshoot and resolve this error.
Step 1: Verify Username and Password
The first thing you should do is verify that you have used the correct username and password. Make sure your case sensitivity is correct and that your caps lock key is not on. Also, check whether you are using windows authentication or SQL Sever authentication.
Step 2: Check SQL Server Authentication Mode
If you are using a SQL Server authentication, you need to check the authentication mode configured for your SQL Server instance. You can check this by right-clicking on the SQL Server instance in SSMS and selecting properties. Go to the security tab and check for the authentication mode.
Step 3: Check Server Name
If you are using a server name, you should make sure it’s correct. You can check this by running the SQL Server Configuration Manager and expanding SQL Server Network Configuration. Make sure the instance name is correct and matches with the name you are using.
Step 4: Check If the Database is Online
Another possible cause of the error is if the database is not online. This can happen if the database is not in a state that is operable or online. Try to connect to the database and see if you get any error messages indicating the database is not online.
Step 5: Verify That Your Account Has Access to the Database
Finally, verify that your user account has access to the database. You can do this by going into SQL Server Management Studio and checking the database properties. Go to the Security tab and see if your account has been granted access to the database.
2. Error 4064: Cannot Open User Default Database
This error occurs when SQL Server is unable to open the database specified as the user’s default database. This error can occur when the database is deleted or when the user has been removed from the database. Here’s how to fix it:
Step 1: Connect to a Different Database
The first thing you can try is to connect to a different database. If you can connect to a different database, you can change the default database for the user. You can do this by going into SQL Server Management Studio and going to the database properties. Under the Login dropdown, select a different database as the default database.
Step 2: Reset the User’s Password
Another solution is to reset the user’s password. If the user’s password has changed and the default database does not exist, then you will get this error. In this case, you can reset the user’s password and then connect to SQL Server using the new password.
Step 3: Change Default Database Using T-SQL
You can also change the default database using T-SQL. For example, if you want to set the user’s default database to master, you can run the following command:
| T-SQL Command | Description |
|---|---|
| USE [master] | Sets the current database |
| GO | Terminates the batch of Transact-SQL statements |
| ALTER LOGIN [User] WITH DEFAULT_DATABASE=[master] | Sets the default database for the user |
3. Error 1105: Could Not Allocate Space for Object
This error message is indicative of insufficient disk space in the database or the transaction log. Here’s how you can fix it:
Step 1: Check Disk Space
The first thing to check is whether there is sufficient disk space available for the database or transaction log. You can check this by running the following command in SQL Server Management Studio:
| T-SQL Command | Description |
|---|---|
| DBCC SQLPERF(LOGSPACE) | Displays log space usage statistics for all databases. |
Step 2: Reduce Database Size
If there’s insufficient disk space, you can reduce the database size by shrinking the database. Here’s how you can do it:
- Right-click on the database in SSMS and select Tasks > Shrink > Database
- On the Shrink Database dialog box, choose the file type you want to shrink (Data or Log).
- Choose the amount of space you want to free up in the file.
- Select OK to start the shrink operation.
Step 3: Increase Disk Space
If the above two steps don’t work, then you need to increase disk space. You can do this by adding more disk space to the disk that the database is located on or by moving the database to a different disk.
Step 4: Move Database to a Different Disk
To move a database to a different disk, follow these steps:
- Detach the database from SQL Server
- Copy the database files to the new disk
- Attach the database to SQL Server with the new file location
4. Error 823: I/O Error
This error occurs when SQL Server is unable to read or write data to or from the disk. It indicates a potential hardware problem. Here’s how you can fix it:
Step 1: Verify the Error
The first thing to do is to verify that you have this error. You can do this by checking the SQL Server error log file. Look for an error message that states “I/O error” or “disk error.”
Step 2: Check Hardware
The next step is to check the hardware, including the disk drivers, cables, and storage controller. If you suspect a hardware issue, contact your hardware vendor for assistance.
Step 3: Restore from Backup
If the issue is not hardware-related, then you should restore the database from a backup.
Step 4: Use DBCC CHECKDB
You can also try using the DBCC CHECKDB command to check the consistency of the database.
5. Error 18452: Login Failed for User
This error occurs when a user is attempting to connect to SQL Server using Windows Authentication, but the server doesn’t trust the user. The error message usually says “Login failed for user ‘username’. Reason: Not associated with a trusted SQL Server connection.”
Step 1: Enable Windows Authentication
The first thing to check is that Windows Authentication is enabled in SQL Server. To do this, right-click on the SQL Server instance in SSMS and select Properties. Click on the Security tab and make sure that “Windows Authentication” is selected.
Step 2: Check User Mapping
Another possible reason for the error is that the user does not have access to the database they are attempting to connect to. You can check this by opening the database properties in SQL Server Management Studio and looking at the Security tab. Make sure that the user is listed as having access to the database.
Step 3: Check Local Security Settings
You should also check the Local Security Settings on the client computer. Specifically, make sure that the “Network Access: Sharing and Security Model” is set to “Classic – local users authenticate as themselves.” You can find this setting in the Local Security Policy under Security Options.
Step 4: Verify Group Membership
If the user is a member of a group that has been granted access to SQL Server, make sure that the group is still active and that the user is still a member of the group.
6. Error 823: I/O Error
This error occurs when SQL Server is unable to read or write data to or from the disk. It indicates a potential hardware problem. Here’s how you can fix it:
Step 1: Verify the Error
The first thing to do is to verify that you have this error. You can do this by checking the SQL Server error log file. Look for an error message that states “I/O error” or “disk error.”
Step 2: Check Hardware
The next step is to check the hardware, including the disk drivers, cables, and storage controller. If you suspect a hardware issue, contact your hardware vendor for assistance.
Step 3: Restore from Backup
If the issue is not hardware-related, then you should restore the database from a backup.
Step 4: Use DBCC CHECKDB
You can also try using the DBCC CHECKDB command to check the consistency of the database.
7. Error 3417: Cannot Start SQL Server
This error occurs when SQL Server is unable to start. It can occur for a number of reasons, including insufficient disk space, corrupt database files, or permission issues. Here’s how to fix it:
Step 1: Check Disk Space
The first thing to check is whether there is sufficient disk space available for the database or transaction log. You can check this by running the following command in SQL Server Management Studio:
| T-SQL Command | Description |
|---|---|
| DBCC SQLPERF(LOGSPACE) | Displays log space usage statistics for all databases. |
Step 2: Check Database Files
You should also check whether the database files are corrupt. You can do this by running the following command in SQL Server Management Studio:
| T-SQL Command | Description |
|---|---|
| DBCC CHECKDB([DatabaseName]) | Checks the logical and physical integrity of all the objects in the specified database. |
Step 3: Check Permissions
Finally, you should check whether the SQL Server service account has sufficient permissions to access the database files. Make sure that the account has “Full Control” permissions for the folders that contain the database files.
8. Error 5120: Unable to Attach Database
This error occurs when you try to attach a database to SQL Server but don’t have sufficient permissions to do so. Here’s how you can fix it:
Step 1: Check Permissions
The first thing you should do is check whether the SQL Server service account has sufficient permissions to access the folder that contains the database files. Make sure that the account has “Full Control” permissions for the folder.
Step 2: Grant Access to the Database
If the account already has “Full Control” permissions for the folder, you should check whether the account has been granted access to the database. You can do this by opening the database properties in SQL Server Management Studio and looking at the Security tab.
Step 3: Run SSMS as Administrator
You can also try running SQL Server Management Studio as an administrator. Right-click on the SSMS icon and select “Run as Administrator.”
9. Error 8998: Page Verification Error
This error occurs when SQL Server detects a page verification error on a database page. Here’s how to fix it:
Step 1: Restore from Backup
The first step is to try restoring the database from a backup. This will replace the faulty page with a good one.
Step 2: Repair the Database
If restoring from a backup is not an option, you can try using the DBCC CHECKDB command to repair the database. This command checks the logical and physical integrity of all the objects in the specified database and repairs any issues it finds.
Step 3: Check Disk Space
You should also check whether there is sufficient disk space available for the database or transaction log. You can check this by running the following command in SQL Server Management Studio:
| T-SQL Command | Description |
|---|---|
| DBCC SQLPERF(LOGSPACE) | Displays log space usage statistics for all databases. |
Step 4: Check Hardware
If none of the above steps work, then it’s possible that you have a hardware problem. Check the hardware, including the disk drivers, cables, and storage controller. If you suspect a hardware issue, contact your hardware vendor for assistance.
10. Error 262: CREATE DATABASE Permission Denied
This error occurs when a user attempts to create a database but doesn’t have sufficient permissions to do so. Here’s how to fix it:
Step 1: Grant Database Creation Permissions
The first step is to grant the user permissions to create a database. To do this, you can use the following T-SQL command:
| T-SQL Command | Description |
|---|---|
| USE [master] | Sets the current database |
| GO | Terminates the batch of Transact-SQL statements |
| CREATE LOGIN [Username] WITH PASSWORD=[‘password’] | Creates a new login with a password |
| GO | Terminates the batch of Transact-SQL statements |
| CREATE USER [Username] FOR LOGIN [Username] | Creates a new user for the specified login |
| GO | Terminates the batch of Transact-SQL statements |
| EXEC sp_addrolemember ‘dbcreator’, ‘Username’ | Adds the user to the dbcreator role |
| GO | Terminates the batch of Transact-SQL statements |
Step 2: Run SSMS as Administrator
If granting permissions doesn’t work, you can try running SQL Server Management Studio as an administrator. Right-click on the SSMS icon and select “Run as Administrator.”
Step 3: Use a Different User Account
If none of the above steps work, then you should try using a different user account that has the necessary permissions to create a database.
11. Error 18461: Login Failed for User Because the Account is Currently Locked Out
This error occurs when a user attempts to log in to SQL Server but their account is locked out. Here’s how to fix it:
Step 1: Identify the Account
The first step is to identify the account that is locked out. You can do this by checking the SQL Server error log or by using the following T-SQL command:
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