The appointment was made by distressed investor Agilo, who are believed to be owed around £4.5m. Palace have total debts estimated to be £30 million and need to raise about £4 million to see out the season.
Guilfoyle told reporters: "We have been appointed by a lender. Agilo exercised their right to appoint an administrator and from the point of view of the board of directors it was unwelcome and unanticipated.
"But since I've arrived at 3.30pm this afternoon I have had good co-operation with Dominic Jordan (vice-chairman) and Simon Jordan, who is devastated but has said he will co-operate in rescuing the club."
The club's players and staff are set to be paid their January wages tomorrow after Agilo loaned £1million to administrators P & A Partnership.
Guilfoyle said: “The staff will be paid on Tuesday because I have negotiated a million pound facility with those that appointed us."
"We are hoping our appointment will be short-lived as we understand there are many interested buyers."