How to solve missing DLL xpSLS.dll issue on SQL Server Instance

I recently performed an in-place upgrade of a SQL Server from SQL 2012 to SQL 2016. All seemed to work fine, until our nightly database backups failed.

This SQL Server uses LiteSpeed for backups and the following error was being returned when it ran:

Msg 17750, Level 16, State 0, Procedure xp_backup_database, Line 1
Could not load the DLL xpSLS.dll, or one of the DLLs it references. Reason: 126(The specified module could not be found.).

After a quick file search on the server I found out the errored DLL was located under D:\Program Files\Microsoft SQL Server\MSSQL…MSSQLSERVER\MSSQL\Binn folder. And, I can tell that this path definitely belongs to a SQL 2012 directory.

The SQL Server 2016 files installed in a different directory, and the DLL used by LiteSpeed was not under that directory.

I copied the file to the corresponding location in the SQL 2016 folder

D:\Program Files\Microsoft SQL Server\MSSQL…MSSQLSERVER\MSSQL\Binn

After the missing file has been replaced, backups started to work.

When we are planning upgrade the SQL Servers, we usually tend to think about how the database engine works between different versions and we mostly focus on if an upgrade will cause any application issues.

It’s extremely easy to overlook third party applications. And even if we verify those applications are compatible the version that we will be upgrading, it’s often easy to overlook some simple facts – like program paths will be different after an upgrade.

Please contact us  if you need help resolving SQL Server issues you need resolved.

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