Installing Linux Mint at the partitioning window it sometimes does not give the radio button saying Install Linux Mint alongside them.

This is even though it recognizes that a Windoze is on the disk.

Anyone, know why it sometimes does and sometimes doesn't allow the dual boot option?

Are these detections using the same install media (same version) and on the same PC?

No different media been going on for a long time.

Used 18.1 and 18.2 and 32 bit and 64 bit.

Any ideas?

I would look for differences in the BIOS settings and hardware, as well as the version of Windows installed. I have always installed both, with the traditional bios rather than UEFI, all safe mode settings turned off. I have never run into that issue. It could be the way I run, or I may just have been very lucky.

If you are installing on a pre-loaded PC with the OEM versions of Windows, they will be set up by the hardware and Microsoft default settings. This is often not optimal for a dual boot machine, and Microsoft assumes they get to use the entire machine the way THEY want. I have done this install often, but not often with Mint.

I doubt if I will have any answers for you, but I do find the question interesting. I suspect that we will need much more information about each individual install so that we can compare all of the details for those instances where the prompt presented properly against those where it did not.

Have you opened the question on the MINT site forums? I would look there first to see if it is a known issue.

Thanks I think windoze 7 is OK but Advent 4212 notebook using Windows Vista and Acer Aspire One with Windoze XP were ones. Windows 7 seems to work on other machines.

Best Regards