Why does my Social Security card say not valid for employment?

Or, it may also say "Valid for work only with DHS authorization."  This is a question perplexing many DREAMers approved for DACA, which supposedly lets them work legally because of having approved for a work permit, and having an employment authorization document (EAD).  So what is going on here?  Is this a mistake?

Not at all.  The Social Security Administration issues a card that has the name and the number to individuals who are US citizens or permanent residents.  It is an indication that these people are authorized to work at all times without conditions.

If your card says "Valid for work only with DHS authorization," it means that you have been authorized to work on a temporary basis.  In other words, this card is valid as proof of work, only when accompanied by a work permit.  This card is no longer valid as evidence of legal employment the day your work authorization expires.  It is your legal duty to renew your work authorization in a timely manner so that there is no gap.  If it does happen that you work permit is not renewed before the previous permit expires, you should let your employer know and stop working till you receive your new document.  Working without authorization is a crime and can hurt your prospects of receiving further immigration benefits.  If your renewal is denied, you are no longer allowed to work, and in your best interest, you should not work.  Depending on the type of visa you have, it does not mean that you have to leave the country, but some work related visas are tied to your employment, so with the expiration of your work permit, you may have also lost your right to stay lawfully in the country.  Discuss this with your attorney so that you do not accrue unlawful status in the country.

Immigrants who receive a card with the words "Not valid for employment" are given a number for other purposes but not for employment.  These individuals are barred from work and if they do change their immigration status and are able to work, they must do the paperwork to get a new Social Security card.

In all cases, it is important to understand that once you are assigned a SSN, it is for yours to keep for life.  So as you change your status or lose your right to work, your number will still be the same.  It confers no other rights on you like being able to live in the USA, get a driver's license or work.