Meghan Markle has lost the first stage of her High Court case against the publisher of the Mail on Sunday newspaper, it was announced on Friday.
A judge decided that parts of the case should be struck out, though he said these could be revived at a later date.
The case concerns a letter written by Meghan to her estranged father Thomas Markle in August 2018, parts of which were published by the Mail on Sunday and MailOnline the following February.
Meghan is seeking damages for alleged misuse of private information, copyright infringement, and breach of the Data Protection Act by Associated Newspapers, which is also the publisher of MailOnline.
Mr Justice Warby delivered his ruling following an application by Associated Newspapers last week.
He struck out three allegations from the case, including that Associated Newspapers acted "dishonestly and in bad faith", that it "deliberately dug up or stirred up" conflict between Meghan and her father, and had an "obvious agenda of publishing intrusive or offensive stories" about her.
"The grounds of attack on each aspect of the case are that the allegations are irrelevant in law, or inadequately particularised, or that it would be disproportionate to litigate the issues raised so that they should be excluded from the scope of the case on case management grounds," the judge wrote.
The first hearing was held remotely last week because of the coronavirus, with Meghan and her husband Prince Harry listening from Los Angeles.
Meghan's lawyers have accused Associated Newspapers of "harassing, humiliating, manipulating and exploiting" her father, whom they describe as "vulnerable”.
The legal action was announced in October last year via a statement in which the Duke of Sussex accused newspapers of a “ruthless campaign” against his wife.
Meghan and Harry recently announced they were cutting off the Daily Mail and three other British tabloids, giving them "no corroboration and zero engagement", saying that their coverage has been unfair.
Lawyers for the firm representing Meghan said the ruling does not change the "core elements" of the case.
“Whilst the Judge recognises that there is a claim for breach of privacy and copyright, we are surprised to see that his ruling suggests that dishonest behaviour is not relevant. We feel honesty and integrity are at the core of what matters; or as it relates to the Mail on Sunday and Associated Newspapers, their lack thereof," a Schillings spokesperson said.
"Nonetheless, we respect the Judge's decision as the strong case against Associated will continue to focus on the issue of a private, intimate, and handwritten letter from a daughter to her father that was published by the Mail on Sunday."