NevilleGoddard wrote:I'm just saying that if you install another OS on the machine and something goes wrong with it under the warranty period, they may not look at it. I live in Japan and I think you live in Europe you your consumer protection laws may be a bit more friendlier than here so you may not have a problem. I've heard that here in Japan if you put one sticker on the outside of your phone and something goes wrong with it, they'll tell you to get lost and refuse to look at it.
I'm just saying that you may want to contact them first before you install to see if it's OK to save yourself some headaches later.

Worth to note that at least some maker (Dell, that I know of, at least the last time I bought from them), allow you to send back a notebook without the hard disk (that may contain sensitive data), implying without an operating system, and that of course doesn't invalidate the warranty.
NevilleGoddard, I know that there are scammers out there that would do anything to not apply the warranty, but the serious makers already knows it is a big error.
Then, if instead we talk about "support", that's a different thing, likely they will support only the OS they provided with the product, and I guess that can be seen as a "reasonable behavior".
Even if the laws in EU may be seen in favor of the consumers, in practice it is not that relevant, I have already seen cases where the repair of an item require several months ... a fact that speak for itself; what is always relevant are the maker and seller reputations.