The Dutch PM famously used an old Nokia mobile, but has since changed it for a modern smartphone following the text archive controversy.
Dutch Prime Minister Mark Rutte failed to properly archive messages on his old mobile phone, an official report said on Monday.
Nicknamed "Teflon" by the Dutch media for his ability to survive scandals, Rutte said in May that he had archived all important messages, but deleted others to free up space on his old Nokia.
"The Prime Minister's chat messages are (...) insufficiently archived," the Dutch government's information and heritage inspectorate concluded in its report.
Many messages "have been deleted", the inspectorate noted, without being able to specify how many of them should have been kept according to Dutch archive law.
And the officials who archived the messages did so according to "a government instruction (...) which does not seem to comply with the archive law", the report also found.
Rutte, who has been head of government for 13 years, almost always sent his incoming messages to an official for archiving, but the report found this wasn't always the case with outgoing messages.
The report also found the way Rutte's messages were archived led to a loss of data because they forwarded messages didn't show the time they were originally received.
"Good archiving is important to know how things happened," the inspectorate said.
The Dutch daily de Volkskrant revealed Rutte's method of archiving text messages back in May, after they sought access to government communications covering the COVID pandemic period.
Rutte's devotion to an old Nokia phone has helped burnish his image with the public of someone who lives a simple and frugal lifestyle.
After the controversy, Rutte - who is also known for cycling around The Hague - swapped his old phone for a new smartphone.
On Monday, Rutte said his office would look into a possible change in government instructions on archiving messages.