What situation are not allowed to use standard deductions

[VolvoGirl]

Only one I can think of.  If you are filing as Married filing Separate and your spouse itemizes then you must also itemize, even if it is less than the Standard Deduction or zero.  Unless you are filing Head of Household.   

If it's giving you the Standard Deduction and  not showing you Schedule A you can check the actual amount of itemized deductions by using by going to

Tax Tools on left

Tools - Topic Search (top left box)

Type in  itemized deductions, choosing.  It should highlight that in the list, click on GO

Then Click on "Change my deduction". That will display the actual amount of itemized deductions vs. the standard deduction.    (Be sure to uncheck "Change my deduction" after checking it so you do not lock in the wrong deduction.

How to change between the Standard Deduction and Itemized Deductions

https://ttlc.intuit.com/community/accessing/help/how-do-i-change-from-the-standard-deduction-to-item...

[Critter-3 · Accepted solution]

You have the option to use the standard deduction or the itemized deductions whichever is larger   EXCEPT  if you are filing separetly from your spouse.  Then if one of you itemize the other MUST itemize even if the standard deduction is larger.  

[NCperson]

@meloveh110 the other situation I can thing of - and is a matter of semantics - is a dependent child.  They still have a standard deduction, but it is not calculated the same way as it is for most other tax payers. 

Why are you asking? 

[rjs]

A nonresident alien cannot use the standard deduction, except for students and business apprentices from India. But a nonresident alien also cannot use TurboTax.

Instead of looking for a list of rules that might or might not apply, what is your specific situation? Why do you think that you might not be able to use the standard deduction?