Wow, I’d just like to say that I am having the exact same issue. Exact same issue. I came here boiling with frustration and hoping someone could help. If anyone knows what is up, please weigh in.
At this point I want to take Mor10 and hurl him into a black abyss.
If after a migration you land on the WordPress installer page, it almost always means the database prefix in your migrated database does not match the table_prefix value in wp-config.php. Without matching tables, WordPress asks for new ones to be created through the install process.
From what I can tell, DesktopServer uses the standard table prefix “wp_”, so my guess is the site you are exporting from has a different prefix. It is also possible the prefix in your particular DesktopServer site has a different prefix.
To find out, open wp-config.php in your DesktopServer install and look for table_prefix. Make sure the prefix defined there matches the prefixes in the database tables of your exported site (you see them in phpMyAdmin at the beginning of each table name.) If the prefixes do not match, you know what the problem is. To solve this, you can either try to change the table_prefix setting in DesktopServer (just remember what the original setting was in case you want to switch back), or you can use the automatic Pull feature in WP Migrate DB Pro to handle the transfer seamlessly.
For reference, this particular issue is addressed in the course in the movie called “The importance of matching table prefixes”: https://www.lynda.com/WP-Migrate-DB-Pro-tutorials/importance-matching-table-prefixes/472837/476570-4.html