Plaintiff is injured at work and sues the third-party.  Plaintiff asks attorney whether she may sue her employer.  The answer is "No", isn’t it?  After all, one may not sue one’s employer, correct?

In a fine example of how much investigation may be necessary, Thompson v Seligman
2008 NY Slip Op 06496 Decided on July 31, 2008 Appellate Division, Third Department  reports that plaintiff has raised a question of fact whether defendant attorneys investigated enough.  It turns out that plaintiff was not employed by the entity where she worked.
 

"Plaintiff was employed by AMFAC Recreational Services, Inc., which had contracted to regularly provide the Gideon Putnam Hotel with cleaning persons. Plaintiff was injured while she was cleaning rooms at the Gideon. She retained defendant Raymond J. Seligman and his law firm to represent her in a claim for workers’ compensation benefits. Plaintiff also inquired about suing the Gideon for recovery for pain and suffering. Seligman informed her that she could not pursue such a claim, based upon his mistaken belief that she was employed by the Gideon. By the time that plaintiff consulted with a different attorney who advised her that she could have brought a third-party claim for pain and suffering, the statute of limitations had expired. "