How to shrink vRanger Catalog DB (4045788)

Catalog DB is extremely big (if attached to a full version of SQL) or has reached a physical filesize limit for SQL Express.

Queues table takes most of the space (about 80-90% of the total DB). Following command executed in SQL Management Studio can confirm.
EXEC sp_MSforeachtable @command1="EXEC sp_spaceused '?'"
Per Developers, this table should not contain any rows between backups.

Purge data from Queues table. Use truncate command, it is faster than delete

-- script begin
USE master
truncate table [Catalog].[dbo].[Queues]
DBCC SHRINKDATABASE (Catalog)
-- script end

Shrink command can take some time to complete.