What problems will I cause by installing SQL Express as MSSQLSERVER?

Question

As with the people in this feedback doc, Selecting the "Default Instance" option in SQL Server 2008 Express RTM has no effect, I had to install SQL Server Express 2008 twice before I realised what was I was doing.

The installation defaults to "SQLExpress" even if you select Default Instance. What problems might I cause myself in the future if I install SQL Server Express as the instance "MSSQLSERVER"?

Answer 1

I don't see any major problems - the only restriction you have to be aware of is that if you ever need to install a "full" version of SQL Server onto the same server, you cannot install it as default instance, since that instance name would default to MSSQLSERVER.

But even with SQL Server Express installed as "MSSQLSERVER", you can still easily install a full copy of SQL Server under a different instance name - I don't see any problems in that respect.

Answer 2

I once installed a copy of SQL Server Express 2005 that way. Later on, I installed a beta version of Visual Studio. The result was disastrous: Windows Updates wouldn't run, the uninstaller for both products failed, and I could fix it only by reinstalling Windows.

Now maybe it's fixed in SQL Server Express 2008, but I would not install it as MSSQLSERVER unless it's really necessary.

Answer 3

Here's one problem I caused myself:

http://stackoverflow.com/questions/1965700/what-db-required-to-make-the-silverlight-business-application-template-work

Answer 4

There is no problem with SQL Express itself. It can be installed, updated, uninstalled just fina as a default instance. But there are plenty of problems with various admin tools, development tools, documentation and samples that all assume, sometimes in hard code, that the Express instance will be named 'SQLEXPRESS'. An example of such 'default' is the LocalSqlServer connection string in the machine configuration, as you already found out. There are other, including VS installation scripts and such, as Andomar found out.

So while is possible to have a SQL Express as 'MSSQLSERVER', it will not be considered as the SQL Express instance by many of the tools from development platform, so is better to go with the flow and have a SQL Express named 'SQLEXPRESS' for the benefit of Visual Studio and friends.