Table Partition Switch out problem
Because switching partition change address of all pages to target table, it also moves indexes (created on the source table) to target table. If available index on the table is not partitioned index will not move to target.

When we SWITCH partition, make sure both (source and target) tables has same schema (structure), indexes (should be partitioned) and CHECK constraint.

According to the Error


  Error: ALTER TABLE SWITCH' statement failed. The table
  'ApplicationLogs.dbo.SchedulerLog' is partitioned while index
  'staging_SchedulerLog_20160923-120700_pkSchedulerLogId' is not
  partitioned.


The index [pkSchedulerLogId] is not partitioned.

After you partition the index

DROP INDEX [pkSchedulerLogId] ON [dbo].[SchedulerLog] WITH ( ONLINE = OFF )

CREATE UNIQUE NONCLUSTERED INDEX [pkSchedulerLogId] ON [dbo].[SchedulerLog] 
(
    [ID] ASC
    ,[Date]
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON)
ON [sch_SchedulerLog]([Date])


AND

either add check constraint to both tables

ALTER TABLE [dbo].[staging_SchedulerLog_20160923-120700]  WITH CHECK ADD  CONSTRAINT [chk_staging_SchedulerLog_20160923-120700_partition_1] CHECK  ([Date]&lt;=N'2016-06-30T23:59:59')
ALTER TABLE [dbo].[SchedulerLog]  WITH CHECK ADD  CONSTRAINT [chk_staging_SchedulerLog_20160923-120700_partition_2] CHECK  ([Date]&lt;=N'2016-06-30T23:59:59')


OR

remove constraint from staging table.

ALTER TABLE [staging_SchedulerLog_20160923-120700] DROP CONSTRAINT [chk_staging_SchedulerLog_20160923-120700_partition_1];


Now you will be able to SWITCH partition

ALTER TABLE [dbo].[SchedulerLog] SWITCH PARTITION 1 TO [dbo].[staging_SchedulerLog_20160923-120700];


Thanks