Typically when you click the 'Export to Excel' menu option to export Test cases to Excel, you will be shown with the screen below:



After you click the OK button, you will be shown with the popup below:



If you don't see this popup at your end, this could be because the snapshot_isolation_state setting is turned off in the SCTM SQL Server database.

Run the following query against your SCTM database in SQL Server.
SELECT snapshot_isolation_state_desc from sys.databases where name='{database name}'

Note : Replace the {database name} with the corresponding SCTM database name.

If the query returns the output as 'OFF', run the command below to turn on the option:

ALTER DATABASE {database name}
SET ALLOW_SNAPSHOT_ISOLATION ON

After the alter statement is run successfully, restart your SQL Server database instance. 'Export to Excel' option should work fine now.