No date for a retrial of Hubert Zafke has yet been set after the proceedings were derailed by complaints that the judges were biased.
"When this will happen we cannot say yet," Carl Friedrich Deutsch, a spokesman for the court, said in a statement.
Zafke had faced charges of at least 3,681 counts of being an accessory to murder in the concentration camp in Nazi-occupied Poland.
But concerns over his mental and physical health had led to repeated postponements of the trial in the northeastern lakeside town of Neubrandenburg.
Over the last few hearings, a parade of doctors have been quizzed about Zafke's mental health, reaching contradictory conclusions.
Prosecutors, and civil plaintiffs, had in turn launched motions of bias against the judges, charging that they were unwilling to try wheelchair-bound Zafke.
Deutsch said the prosecutors had asked three judges to recuse themselves.
There was insufficient time to decide whether to grant or reject these requests before the next scheduled hearing next Monday.
The spokesman added bluntly that he couldn't understand why prosecutors would employ a legal tactic that left them open to charges they had "torpedoed the proceedings which they themselves had launched".
Anne Frank in Auschwitz
The charges against Zafke focus on a one-month period in 1944 when 14 trains carrying prisoners - including the teenage diarist Anne Frank - arrived at Auschwitz-Birkenau.
Frank, who arrived in Auschwitz with her parents and sister, was later transferred to another camp, Bergen-Belsen, where she died in March 1945, just two months before the Nazis were defeated.
Thursday's announcement marked the end of a case that had been marred by five delays and at times deteriorated into farce, increasingly frustrating victims' lawyers.
The International Auschwitz Committee, which represents Holocaust survivors, had sharply attacked Germany's handling of the case, saying the court was hurtling "between sloppy ignorance and complete disinterest" in a resolution.
Some 1.1 million people, most of them European Jews, perished between 1940 and 1945 in Auschwitz before it was liberated by Soviet forces.
More than 70 years after the prosecution of top Nazis began in Nuremberg, Germany has been racing against time to try the last Third Reich criminals.
Zafke was the fourth former concentration camp worker in the dock in the latest series of trials, following John Demjanjuk in 2011, Oskar Groening in 2015 and Reinhold Hanning this May - all convicted of complicity in mass murder.
Those cases were hailed for providing a degree of catharsis for aged survivors, even if they shed little new light on the Holocaust.