WASHINGTON — President Trump’s advisers have concluded that a wide-ranging corruption investigation into his personal lawyer poses a greater and more imminent threat to the president than even the special counsel’s investigation, according to several people close to Mr. Trump.

As his lawyers went to court in New York on Friday to try to block prosecutors from reading files that were seized from the personal lawyer, Michael D. Cohen, this week, Mr. Trump found himself increasingly isolated in mounting a response. He continued to struggle to hire a new criminal lawyer, and some of his own aides were reluctant to advise him about a response for fear of being dragged into a criminal investigation themselves.

The raids on Mr. Cohen came as part of a monthslong federal investigation based in New York, court records show, and were sweeping in their breadth. In addition to searching his home, office and hotel room, F.B.I. agents seized material from Mr. Cohen’s cellphones, tablet, laptop and safe deposit box, according to people briefed on the warrants. Prosecutors revealed in court documents that they had already secretly obtained many of Mr. Cohen’s emails.

Mr. Trump called Mr. Cohen on Friday to “check in,” according to two people briefed on the call. Depending on what else was discussed, the call could be problematic, as lawyers typically advise their clients against discussing investigations.