In TaxSlayer Pro, upon exiting Maryland Form 510 or Form 511 being prepared for an S corporation, you will be told that it needs to be filed separately from the federal return:
MD requires e-filed S Corporation returns to be sent as unlinked returns.
Please transmit your MD return state-only.
This is a limitation of the Maryland e-file system for the S corporation return, and Form 510 or 511 being filed for an S corporation will reject if filed linked to the federal return with code R000-00000-100:
Reject Code: R000-00000-100 | Category: Incorrect Data | Severity: Reject and Stop
All Forms 510, 510D, and 510E with entity type sCorp must be transmitted as unlinked returns with SubmissionCategoryCd PART in State Submission Manifest.
*** Additional Information: Incorrect Data ***
Additional Information: