You don't need to export to Excel to do the comparison, you can do it directly in SQL Server.

Look at the files on the drive and see if there is a large, obsolete file(s) (perhaps old backups?).

Depending on the version of SQL Server, you might also be able...

Try this.  It may not work because of the GROUPing.  You might have to do the GROUPing after concatenating the subquery results.

SELECT
DISTINCT 
G.[Period], 
G.[Sector], 
G.RID, 
STUFF
((
SELECT 
DISTINCT
...

Is your tempdb database on the C: drive?  If so, that could theoretically cause the problem.

By the way, 9GB is a very tiny amount of free space on a drive. ...

I don't think you can do much for that table itself.

You need to look at the code that is UPDATEing that table and make sure that code is efficient.  Also,...

Would you be able to use TRUNCATE TABLE instead to remove all the rows?  That will be vastly faster.

If the table has an identity column, and you want to maintain...

The inserted and deleted "tables" only exist within the direct code of a trigger.  You can't reference them from an external query.  You'd need to write the inserted and deleted...

This is somewhat confusing, but something like this would likely do what you want to do:

SET ANSI_NULLS ON;
SET QUOTED_IDENTIFIER ON;
GO
CREATE TRIGGER [dbo].[tr_ORDERID]
ON [dbo].[MYCUSTOMERS]
AFTER UPDATE
AS
SET NOCOUNT ON;
BEGIN
IF UPDATE(ORDERID)
BEGIN
...

synchronous

Code only needs to be schedule on the first and last Thursday of the month, since those are the only 2 days it might need to do something.

As to simplification,...

The worst schema I had to implement: A customer wanted us to reboot the server for patches on the first friday of the month around 1am.

How do you...

(Dup post, removed)

;WITH cte_data AS (
    SELECT CAST(50.10 AS numeric(5, 2)) AS HRS
    UNION ALL
    SELECT 50.77
)
SELECT HRS
FROM cte_data
WHERE HRS...

LineCount must exist in your table, not the system table; if so, then change the alias before the column name:

...

INSERT INTO dbo.PrimaryHist

SELECT 'UPDATE'

,s.login_name

,i.batch_id

,i.LineCount --<<--

FROM INSERTED AS i

CROSS JOIN sys.dm_exec_sessions AS...

Page compression is generally very effective at reducing data size.  But you will need to either: (1) shrink the data file after compressing, which will take a long time and...