Did you test and compare both queries execution plans?

In general, I prefer using JOIN ( and only switch to alternatives when proven way better for that given solution...

does the sql server service account have write access to the given path?

as my devs often say: 'the server must have had a hiccup' 😉

Let's hope SSC gets this fixed.

have you tried adding :
and ( ( b.balance > 10
          OR b.balance < 0 )
       and e.eligibility in ('F', 'R')    )     

First of all: keep calm
- What's registered in the SQLServer errorlog file ?

That info is to be found in msdb!

/*
Backup overview for current database
*/

Declare @BU_DbName sysname
Set @BU_DbName = db_name()

select ...

No input parameters have been defined for the itvf because of dynamic "where clauses needs" by the dev team
(otherwise I would have transformed it into a stored procedure in...