My paperwork was submitted to the government about a month and a half ago for my TS SCI. Will I get some type of notification for when my background investigation will start?
No, the only indication you will get is either a call from an investigator to set up an interview, or a “soft pull” will show up on a credit check. Maybe someone you listed as a reference will let you know that they were contacted by an investigator.
Is it a guarantee that I will have an interview with an investigator or is it on a case by case basis?
A subject interview a required for a TS.