Different (merged) partitions on GParted when installing Ubuntu alongside Windows

Solution 1:

It sounds like you tried to create a partition for Ubuntu using the Windows partitioning tool. This was a mistake, since the Windows partitioning tool converts from standard disk partitions to Microsoft's proprietary LDM/"dynamic disk" whenever the number of partitions exceeds four. Without more detailed information, I can't be 100% positive that this is what happened, but my hunch is that it was. Unfortunately, Microsoft provides no easy way to undo this change. I've heard that some third-party Windows tools, such as EaseUS Partition Master, can make this change, but I've never tried such tools.