Have you ever encountered an error while trying to start SQL Server services after applying a patch? One common issue is related to missing DLL files. In this article, we will discuss a real-life scenario where a customer faced a similar problem and how it was resolved.

When the customer attempted to start SQL Server services after applying a patch, it failed to start. To troubleshoot the issue, the first step was to check the ERRORLOG file. The ERRORLOG provided valuable information about the problem:

2017-05-01 11:04:40.00 spid5s Error: 17750, Severity: 16, State: 0.
2017-05-01 11:04:40.00 spid5s Could not load the DLL xpstar.dll, or one of the DLLs it references. Reason: 126(The specified module could not be found.).
2017-05-01 11:04:40.00 spid5s Uploading data collector package from disk: Install\SqlTraceCollect.dtsx
2017-05-01 11:04:40.00 spid5s Uploading data collector package from disk: Install\SqlTraceCollect.dtsx
2017-05-01 11:04:40.00 spid5s Error: 4861, Severity: 16, State: 1.
2017-05-01 11:04:40.00 spid5s Cannot bulk load because the file “Install\SqlTraceCollect.dtsx” could not be opened. Operating system error code 3(The system cannot find the path specified.).

The ERRORLOG clearly indicated that the DLL file xpstar.dll or one of its dependencies could not be found. Upon checking the BINN path (E:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Binn), the DLL file was present, which made it unclear what the problem could be.

Further troubleshooting involved attempting to start SQL Server from the command line using the following options:

NET START MSSQLSERVER /m /T3608 /T902

However, when trying to connect to SQL Server via SQLCMD, another error was encountered:

SQLCMD.EXE – System Error
The program can’t start because ATL100.DLL is missing from your computer. Try reinstalling the program to fix this problem.

It was now evident that ATL100.dll, a dependent DLL, was missing from the system. After conducting some research, it was discovered that ATL100.dll comes from Visual Studio Shell (vc_red.msi).

The solution to this problem involved two steps. First, the customer was advised to install Visual Studio Shell from the SQL media. Secondly, they were instructed to copy the missing ATL100.dll file from a working machine.

Once the missing file was copied, the customer was able to connect to SQL Server using SQLCMD and start SQL Server normally.

It is important to note that DLL errors in SQL Server can be caused by various factors, such as missing or corrupted files, incorrect installations, or conflicts with other software. In such cases, it is crucial to identify the specific DLL causing the issue and take appropriate steps to resolve it.

Remember, troubleshooting DLL errors in SQL Server requires a systematic approach and may involve seeking assistance from technical support or consulting relevant documentation.

We hope this article has provided you with insights into resolving DLL errors in SQL Server. If you have any questions or would like to share your experiences, feel free to leave a comment below.