On the SP2010 platform, this migration was simply done using a backup and restore procedure. As we found lately this is no longer supported on SharePoint 2013 e.g. you could not restore a site from a server with one cumulative update to another with a higher CU level or from SharePoint Foundation 2013 to SharePoint Server 2013.

We have found a workaround which some may argue is a better approach. This TechNet article explains the need for this workaround and gives further background.

The following workaround will allow you to complete the following:
1. Move a site from SharePoint 2013 Foundation (April 2013 CU) to SharePoint 2013 Server (April 2013 CU) – Confirmed
2. Move a site from SharePoint 2013 Foundation (RTM) to SharePoint 2013 Foundation (April 2013 CU) – Confirmed.

Note: This suggests that this procedure will work when moving a site from any lower CU to any higher CU version.

Backup SQL Database on Source Server

1. On the Source Server: Identify the Database on the Source Server. Do this in Central admin –> Application Management –> View All Site Collections. Click on the site collection and reference the Database Name which houses it.
2. Open SQL Management studio and Backup the database. To do this expand the databases folder and right-click on your Database Name you identified earlier and choose Tasks –> Backup
3. Once you DB is backed up transfer it to a location on your Destination Server. Optionally compress or Zip the database first.

Restore the SQL Database Backup to the Destination Server

1. On the Destination (Database) Server: Open SQL Management studio and Restore the database. To do this right click on the databases folder and choose Restore Database. Optionally rename the Database to whatever makes sense.
2. Open SharePoint Central Administration. Choose Application Management –> then choose Manage content databases and select Add content database. Choose the correct web application on the top right of the screen. Then give this new database the same name as the one you choose during the restore on point 1 above.
   IMPORTANT: It is essential that you choose exactly the same name as the database is seen in SQL Management studio.
3. Now you will see your site collection listed in view all site collection under application management. You’re almost there!
4. If you moved from a server with a different domain or active directory you must now change the collection administrators for that site collection to your own domains administrators. Technically you should now be able to view the site in a browser but there is one last step!
5. To finish you now need to Upgrade the content database you restored earlier so that it is running on the same version as you own local SharePoint installation version or cumulative update level. To reference this in Central Administration choose Upgrade and Migration level and choose Review Database Status Level. You should see you database has a status of “Database is in compatibility range and upgrade is recommended”.To do this simply open management shell run as administrator and run the following single command referencing your database name.

Upgrade-SPContentDatabase –Identity <name_of_contentDB>

This can take about 3-4 minutes depending on the site collection size.

You’re Done!

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