Question: Is there any way to move all SSRS reports from one server to other, other than downloading each .rdl file and uploading them one by one to the new one?

I followed the steps in [this forum post on MSDN](https://social.msdn.microsoft.com/Forums/sqlserver/en-US/07e55ad1-ffbd-4e54-ace6-3c7bddf516ee/migrate-ssrs-reports-from-one-server-to-another?forum=sqlreportingservices), but no use.

Answer: 
I have a blog site with an article on how to perform this task and common errors you might encounter and how to fix it. 
<https://samosql.com/2017/10/25/migration-of-ssrs-to-another-instance/>

Summarized Steps:

* Migrate the Source ReportServer Database (including the ReportServer Tempdb) to the target server. NOTE: There are various ways of achieving this - with Backup and Restore | Detach and Attach. The easiest way however is using backup and restore as it preserves the permission settings.
* Using the Reporting Config Manager, perform a backup of encryption key and provide a strong password. Note password as it will be require when restoring on target server.
* Restore encryption key using the strong password created on the target reporting services using reporting config manager.
* Using the Reporting Config manager, configure the report server database connection.
* Restart the SQL Server and Report Server Services.

Possible Issues:

* RSExec role do not exist in the master and msdb on the target server.
FIX: Create the RSExec role in the respective databases
* The feature "Scale-out deployment" is showing old server. Use Reporting Configuration manager to delete the old server name.

Few Checks:
Any schedules or subscriptions on the old server should migrate and be automatically created on the target server (Agent jobs)
Visit Report Portal and confirm that reports and permissions migrated properly

Feel free to comment on the article with questions or concerns.

HTH
MS has a detailed instruction here

<https://learn.microsoft.com/en-us/sql/reporting-services/install-windows/migrate-a-reporting-services-installation-native-mode>