Migrating a TFS Project collection from one TFS environment to other needs to be planned before execution.

As part of the planning,  you should make sure the below points.

1. Make sure the source TFS server and Target TFS server are on same patch level

2. Make sure you are having same sql server version on Source and Target [Higher version at Target is also ok]

Once the above points are verified, follow the below steps.

1. Login to the TFS App sever (in Source), open TFS Admin Console. From the administration console, highlight the name of the collection that you want to delete, and then choose Detach Collection.From the administration console, highlight the name of the collection that you want to delete, and then choose Detach Collection.

Detach a team project collection

2. Login to the SQL server, take a full backup of the backup of the collection database. Once a backup is take you can reattach the collection, using attach collection link in the consol. Reattaching the collection is not mandatory if the source database is not going to be used.

3. Copy the database backup to the target TFS environment's SQL Server and restore the database from backup file.

4. Go to the TFS Admin console in the Target Server and click on attach collection. You will have all your team project in the target environment.