The Snicket File is important information.
In the books
The Snicket File is a compilation of 13 pages of information that were temporarily stored in the Library of Records at Heimlich Hospital under "Baudelaire". It contains information that would be able to convict Count Olaf and his associates of various crimes as well as (presumably) information about fires, including the fire that destroyed the Quagmire home. It also had information about Hotel Denouement being the last safe place.
The file was removed from the Library of Records for an investigation, but the last page was left behind. Who conducted the investigation is unknown, but the file found its way into the hands of the Man With a Beard But No Hair and the Woman With Hair But No Beard. In The Slippery Slope, they gave the file to Count Olaf. They said it contained information that could land all three of them in jail. Afterwards, the file was never mentioned nor referenced again in the series.
The final page of the file was later recovered by the Baudelaire orphans. That page had a single sentence and a photograph clipped to it. The photograph was of their parents, Jacques Snicket, and another man on the porch of 667 Dark Avenue. The sentence said: "Because of the evidence discussed on page nine, experts now suspect that there may in fact be one survivor of the fire, but the survivor's whereabouts are unknown." The Baudelaire children took this to mean that one of their parents was still alive. Quigley Quagmire, who had survived the fire that burned down his house, believed that this ambiguous sentence referred to his own survival. Who it actually refers to is never clarified or confirmed.
In The Slippery Slope, the Man With a Beard But No Hair gives Count Olaf a present and the present is the Snicket File. Count Olaf goes somewhere private to look over it.
- It is never explained why the file is called the "Snicket File" but it may have been compiled by a member of the Snicket family.
- The other man in the photograph is commonly believed to be Lemony Snicket.
- Due to the Snicket File never mentioned again after The Slippery Slope, it can be presumed that the files were destroyed.
In the TV series
In the TV series, the Snicket File is portrayed as a film reel, likely to make it more interesting for the visual medium. The Baudelaires first see it in the Library of Records and remember Snicket was Jacques' surname. Unlike the book where it was filed under "Baudelaire", it was filed under "VFD" because Hal was given very specific instructions to label anything with "Snicket" under "VFD".
The Baudelaires play it and see Jacques. Jacques is asked how his brother is, and Jacques replies either dead or on the lam. Jacques is asked what he knows about Olaf and a rash of fires and anything important regarding "the orphans". Jacques vaguely mentions that it seems there is a survivor of a fire, leading the Baudelaires to suspect one of their parents may still be alive. Esmé Squalor interrupts the Baudelaires from viewing any more.
Later, Olaf watches the file and is also angered when he suspects one of the Baudelaire parents may still be alive. The film reel is then burned when Olaf damages the projector and makes
no further appearances in the series.