Migrating from CRM 4.0 to Dynamics CRM 2011

Scenario: You’ve installed Dynamics CRM 2011 on a fresh set of Windows Server 2008 and SQL Server 2008 64-bit servers, and successfully performed a test migration on your CRM 4.0 production organization .
Microsoft refers to this as the “migration” upgrade path, and while it’s not the only approach you can take, it’s probably the best one. Some of the advantages:

Can test an upgrade from CRM 4 to CRM 2011 with no impact on your current 4.0 production environment.
If upgrade fails no impact on production.
Minimal downtime for upgrade (just the time it takes to actually import the CRM 4.0 database into the CRM 2011 format in the deployment manager)

Anyway, you test away for a few weeks, implementing some customizations and maybe even configuring IFD. Your users have been happily updating the CRM 4.0 production database, and now you’re ready to upgrade, so you make a backup (to a BAK file) of the 4.0 SQL Server database, create what will become your production database on the 64-bit SQL Server 2008 in your CRM 2011 deployment, and restore the database to it.
You then go into the much improved CRM 2011 Deployment Manager and run the Import Organization wizard, and when you get to the point to import the organization into CRM 2011 format…you get this message:
“you have already imported and upgraded this organization and cannot perform the operation again…”
And see something like the following screen shot:
migration error

There are lots of questions about it, as you can see if you search Google or Bing for the error message. Not a lot of answers, however. So if you can’t import a 4.0 organization more than once, how can you test?
I’m not quite sure why this would be “by design”, as most of the threads you’ll find say, and it doesn’t seem very elegant, but here’s a workaround:
In CRM 2011

Create a solution package and import any customizations you want to preserve
Export the solution package to the solution XML file

In the CRM 2011 Deployment Manager

Disable the organization.
Then delete it.

In the CRM 2011 SQL Server

Delete the database from SQL Server

In the CRM 4.0 SQL Server

Back up the 4.0 organization database (the one with the _MSCRM after it), to a BAK file on disk.

In the CRM 2011 SQL Server

Create a new database, and restore the .BAK file to it, overwriting everything in the process.

In the CRM 2011 Deployment Manager

Run the Import Organization wizard
Import the SQL database you restored in the previous step
Import the Solution Package with your customizations you saved out to the XML file in the first step.

I know this is a pretty rough writeup. But I’ve run into this twice now, and the first time I made the mistake of not writing everything down! Hopefully this will never make it into Bridget’s List of Things to Know, but it’s definitely in Richard’s List of Things to Know about Upgrading to Dynamics CRM 2011.