Lenovo has confirmed that several of its Yoga laptops are refusing to install Linux-based operating systems.
The Chinese firm said the issue had been caused by its switch to a new storage system, which reads and records data faster than normal.
There had been confusion after one of its employees posted that Linux wasblocked because of an "agreement with Microsoft".
However, Lenovo has denied enforcing a deliberate ban.
The restriction affects PCs sold with the "signature edition" of Windows 10.
The term refers to a promise that "junk" software is not pre-installed alongside the OS to avoid slowing down its operation.
The affected Lenovo laptops have been on sale for months.
But their inability to support current versions of Linux attracted attention after a post on the Reddit news site.
It referred to frustrated users who had been unable to replace Windows 10 with Ubuntu.
Ubuntu is a free Linux-based OS used by schools, governments and consumers, who are attracted to it being both less demanding on a PC's processor than Windows and also less prone to malware.
Ubuntu's developer Canonical says its OS is used by millions of computers
"To improve system performance, Lenovo is leading an industry trend of adopting Raid [redundant array of independent disks] on the SSDs [solid state drives] in certain product configurations," it said.
"Lenovo does not intentionally block customers using other operating systems on its devices and is fully committed to providing Linux certifications and installation guidance on a wide range of products."
It added that once Linux-based operating system developers had updated the necessary code, their products should work on its machines.
One expert said the firm's stance was reasonable.
Microsoft says that Signature Edition-branded laptops offer about 28% battery life than normal ones
"I understand why the buyers feel aggrieved and surprised," said Chris Green, an analyst at the business consultancy Lewis.
"But at the same time they bought a machine with a pre-installed version of an operating system.
"Any such vendor ultimately only offers assurances that their PC works with the version of Windows it comes with.
"If the user then wants to wipe it and install an OS of their choice, it's a case of buyer beware."