I'll add in a vote for clean OS installs too.

If you have Workflow or Quick Fields, one thing to be aware of is that the connection profiles specify the location of the Laserfiche Server by machine name. You will have to update your Quick Fields sessions to point them to the new server. For Workflow, you will have to reconfigure the Subscriber after you move the repository and set up redirects for the running workflows.

An easier way to handle this would be to set up a DNS alias for the new LF Server with the name of the old machine (and decommission the old machine). That way all clients will automatically be redirected to the new server by your domain controller.

Moving Workflow itself is fairly easy:

1. install WF on the new server
2. stop the WF services on the old machine
3. copy over the Workflow volume (the server's configuration wizard on the current server will give you the location of the volume)
4. move the SQL database to the new SQL server, if needed
5. configure WF on the new server and point it to the SQL DB and volume
6. configure the Subscriber

Ideally, you want your drive(s) that hold your volumes to be on a NAS/SAN LUN for easy transfer from one server to another. You can use virtual drives, but in my experience, using iSCSI is easier and compatible with physical or virtual hosts no mater the flavor.

As far as the OS upgrade goes, I have never been a fan of in place upgrades.  I find it is much better to do a fresh install of the OS.  This also means that the VM image of the old machine is ready to be kicked back on if there are any unforeseen problems.  Once the new server is installed and updated, configure the iSCSI Initiator and your volumes are present and ready to go.

If you do an in-place upgrade of the OS, you will still need to reinstall the Laserfiche applications.  So there is really no time saved doing it that way. 

As far as the volumes go, if they are on different machines from the LF server itself, you do not even need to touch them or move them during the upgrade process.  If the volumes are on the same machine as the LF server, you can also leave those in place or move them once the LF server and its components have been moved to another machine.

We performed in place OS upgrades to our DEV and DR servers without a hitch.  We're now in the middle of our second attempt to upgrade our Production server and can't get the repository to attach.  It keeps saying the repository is not configured properly (Error 9025).  There's also a message in the Event Viewer indicating the application is not licensed for SQL DBMS even though I can see MSSQL in the License Manager.  We're currently in a "production down" state waiting for VAR off-hours support.

Any thoughts would be appreciated.