[SOLVED] Windows 10 disappeared during installation of Mage

[borysn]

Hello everybody. I wanted to install Mageia on my PC and keep Windows 10 in dual boot. However, during the installation process, something went wrong (probably I screwed up something with the partitions) and when booting the PC the only option I get is Mageia. Windows does not show up.
I tried to make a clean install of windows 10 from USB, but it does not work: infact, when I am prompted to choose on which of the partition install windows, I am not allowed in any of them because they are not NTFS. So I created (using Mageia) a new partition, formatting it in NTFS, but again the windows installing program will say that they need an NTFS partition.
No worry about any data on the PC, it is a new one so nothing precious is installed on it. But in this moment I have no clue how to install windows on that machine, and I need it.
Thanks in advance for any help.

[ITA84]

I've never used the Windows 10 installer, but I guess the problem could be that Mageia formatted the partition in some way that isn't recognized by Windows (several versions of NTFS exist, and there might be incompatible differences). Can't the Windows installer format the partition on its own?

[borysn]

The windows installer has an option to format the partition, I tried also this one but it does not work. Still says that the partition is in GPT format (which is not true, because is formatted in NTFS, although maybe the wrong version).

[ITA84]

Still says that the partition is in GPT format (which is not true, because is formatted in NTFS, although maybe the wrong version).

Please note that GPT isn't a partition type but a partitioning format: you can partition a drive with GPT (as opposed to MBR, which is an older partitioning format) and have partitions of several types in it (NTFS, Linux, etc...). I suppose the Windows installer you have can't install on a drive that has GPT; looking around a bit, I'm not sure what the correct solution is, but maybe it's just that you started the Windows installer in legacy BIOS mode and not UEFI, and in BIOS mode you can only install on MBR and not GPT. See if it's possible to start the installer in UEFI mode, or if there's a separate installer for UEFI.

EDIT: small correction, as I cited Ext4 as a partition type, whereas it's actually a filesystem; NTFS is a filesystem as well, but I guess the partition type for it is also usually called that

[borysn]

Thanks a lot. Actually, according to the partition I was choosing to install windows, the installer was either asking for NTFS or GPT; GPT requirement appeared on the partition I had formaatted in NTFS. I had the doubt that GPT was "something else", and you confirmed it to me.
Now I found a workaround that should fix the issue on a windows forum, I'll try it tonight when I'll be at home. Thanks for your help for the moment.

[borysn]

looking around a bit, I'm not sure what the correct solution is, but maybe it's just that you started the Windows installer in legacy BIOS mode and not UEFI, and in BIOS mode you can only install on MBR and not GPT. See if it's possible to start the installer in UEFI mode, or if there's a separate installer for UEFI.

This made the job. First thing I'm doing with the fixed PC is thank you for the hint (restarted the installer in UEFI mode and everything was smooth).

[isadora]

Would you please mark this topic [SOLVED]?
You can do so by editing the title/subject of the first message in the topic.
Place [SOLVED] in front of subject/title.

Thanks ahead.