There are 2 manual ways to start Recovering Pending State in SQL Server database that has been marked in recovery pending state:
Solution 1: Mark database in Emergency mode and initiate forceful Repair
ALTER DATABASE [DBName] SET EMERGENCY;
GO
ALTER DATABASE [DBName] set single_user
GO
DBCC CHECKDB ([DBName], REPAIR_ALLOW_DATA_LOSS) WITH ALL_ERRORMSGS;
GO
ALTER DATABASE [DBName] set multi_user
GO
Solution 2: Mark database in Emergency mode, detach the main database and re-attach it
ALTER DATABASE [DBName] SET EMERGENCY;
ALTER DATABASE [DBName] set multi_user
EXEC sp_detach_db ‘[DBName]’
EXEC sp_attach_single_file_db @DBName = ‘[DBName]’, @physname = N'[mdf path]’